No Connection Error When Accessing Other Users Non-Shared Calendar Outlook 365

Question

No Connection Error When Accessing Other Users Non-Shared Calendar Outlook 365

Jon Mercer 1,031

This is not a shared calendar, and it only happens with one employee. No one else has this issue. If they go into the calendar and add someone else's calendar, it says updating for a bit, and then no connection.

Same issue in Safe Mode, so is not an add-on, and there is nothing from Apple in there, everything is Microsoft.
Works fine in OWA, so not an exchange online or exchange permissions issue.
Renamed OST and NST and had them rebuild. Rather not rename the whole Outlook folder, or rebuild the profile since they have a fair number of other mailboxes that need long passwords.
Ran the full Office Repair
Currently running Microsoft® Outlook® for Microsoft 365 MSO (Version 2202 Build 16.0.14931.20128) 64-bit
Ran SaRA for calendar issues. It came up with an error that said there was a permission issue, but unless Outlook has different permissions than OWA, I wouldn't suspect that is the issue.

Jon Mercer 1,031 Reputation points

2022-04-13T15:45:07.687+00:00

As an update, I scorched earth Office 365 by running the office scrubber and renamed the Outlook folder. Rebooted, reinstalled office and still has the same issue. I noticed that it rebuilt everything since all shared email boxes are stored in the OST.

They can access the calendar of shared accounts, but not personal accounts in Outlook, but still can access them in OWA. Are there any other thoughts on this?
Hugo Lemmens 81 Reputation points

2022-05-12T08:00:43.667+00:00
Exactly same problem here, appearing out of nowhere with one single user.
User has a MS 365 Bus Premium licence and runs on Azure Virtual Desktop
Tried all of the above - no improvement.

OWA works fine

toggling offline back and forth - no change

turning cache off - no change

Created same mail profile for that user on a different PC - outside of their AVD environment in Outlook running of a fat client.
Exactly same issue.
Tried to open properties of the non-shared calendar

Hoping someone will find a solution...
Jon Mercer 1,031 Reputation points

2022-05-12T15:29:22.077+00:00

Hoping so also. We ended up having to have the user who they were trying to access their calendar give permission to access the calendar, which they didn't have to do with anyone else.

It is irritating when the person asking a question stops replying, but more so when someone from Microsoft gives a basic answer, and then stops replying when it doesn't work, or they ask you to do something, you ask how to do it, and they don't reply. @Faery Fu-MSFT
Jon Mercer 1,031 Reputation points

2022-05-13T15:23:29.357+00:00

Hugo, that is a good find, theirs for some reason was disabled. I am guessing since she is an older employee, that way before my time, they were turning off everything except for two or three things in there, because all recent employee's I looked at, everything in there is enabled.

Unless it is a propagation thing, it still didn't work, but they also have everything except the first two disabled, so might require multiple things of the list that is left.
Jon Mercer 1,031 Reputation points

2022-05-23T17:55:13.74+00:00

Looks like it wasn't a propagation issue, since with just Outlook on the web, Outlook Desktop (MAPI), and Exchange web service enabled, it still was giving the same error.

I enabled the rest of them, and will see what happens. Most everyone else had them turned on.

[EDIT]

It was somewhere between one or all three of the last three. After enabling all three of them, and giving it a bit, they now can see other people's calendars. I am not going to mess with it since it works, so if others have this issue, and want to narrow down which it is, let us know here if you could.
Hugo Lemmens 81 Reputation points

2022-05-27T07:43:21.337+00:00

Well, if it ain't broke - don't fix it I would recommend. For what it is worth, my bets would be on de Exchange ActiveSync enabling. Glad at the end we found a solution.
Jon Mercer 1,031 Reputation points

2022-05-27T15:19:52.647+00:00

Exchange ActiveSync is my guess also.
Teraleenee 1 Reputation point

2022-06-02T18:02:12.577+00:00

Hello, JonMercer-8382, there are several answers to your question on different forum threads, so I will try to help you with helpful references.

The first hint - reason can be expired security certificates which should be renewed. The second - try to check if everything works on a different OS. This way, you'll make sure it is not a Windows glitch.

Updating/repairing Office can also be useful. Here you can find more details on each step of troubleshooting.

I also recommend using a NAKIVO backup for Microsoft 365 to make sure you can always recover after any system issues.
Jon Mercer 1,031 Reputation points

2022-06-02T18:07:16.783+00:00

Thanks, but none of those are of use. We figured out the issue a week or so ago. See the bottom of this conversation for the full reason, but basically it was a permissions issue in Exchange.
Ijaz Rexvi 1 Reputation point

2023-01-18T01:03:04.0466667+00:00

Hi, I've had the same issue, and tried everything as stated above. The user can access the shared calendar. on the desktop application from another PC, however on the specific PC is states "no connection" for all the shared calendars.

As it works fine on her personnel computer, I've re-installed office application and the issue is still persistent. I've also unchecked the "turn on shared calendar improvements" on the advance settings still with the no connection error.

any ideas or suggestions?
Jake Bloomfield 31 Reputation points

2023-05-25T09:07:55.89+00:00

Hi,

I am having the exact same issue with another user. I've made sure all of the Mail apps in the Admin centre for this user were enabled.. but no dice. Any ideas?

Cheers,

Jake
Daro Chong 0 Reputation points

2025-12-05T02:33:57.04+00:00
I just faced the issue and seems solved with the following command

Troubleshooting steps:

Run PowerShell to reset affected user's EWS:

Install-Module ExchangeOnlineManagement -Force

Import-Module ExchangeOnlineManagement

Connect-ExchangeOnline

Set-CASMailbox -Identity ******@xxx.xxx -EwsEnabled $false

Set-CASMailbox -Identity ******@xxx.xxx -EwsEnabled $true #This will reset the EWS status

Set-Mailbox -Identity ******@xxx.xxx -ApplyMandatoryProperties

The changes on the mailbox might take up to 24 hours to take effect

Answer accepted by question author

1 additional answer

Your answer

Jon Mercer 1,031 Reputation points

2022-04-13T15:45:07.687+00:00

As an update, I scorched earth Office 365 by running the office scrubber and renamed the Outlook folder. Rebooted, reinstalled office and still has the same issue. I noticed that it rebuilt everything since all shared email boxes are stored in the OST.

They can access the calendar of shared accounts, but not personal accounts in Outlook, but still can access them in OWA. Are there any other thoughts on this?
Hugo Lemmens 81 Reputation points

2022-05-12T08:00:43.667+00:00

Exactly same problem here, appearing out of nowhere with one single user.
User has a MS 365 Bus Premium licence and runs on Azure Virtual Desktop
Tried all of the above - no improvement.

OWA works fine

toggling offline back and forth - no change

turning cache off - no change

Created same mail profile for that user on a different PC - outside of their AVD environment in Outlook running of a fat client.
Exactly same issue.
Tried to open properties of the non-shared calendar

Hoping someone will find a solution...
Jon Mercer 1,031 Reputation points

2022-05-12T15:29:22.077+00:00

Hoping so also. We ended up having to have the user who they were trying to access their calendar give permission to access the calendar, which they didn't have to do with anyone else.

It is irritating when the person asking a question stops replying, but more so when someone from Microsoft gives a basic answer, and then stops replying when it doesn't work, or they ask you to do something, you ask how to do it, and they don't reply. @Faery Fu-MSFT
Jon Mercer 1,031 Reputation points

2022-05-13T15:23:29.357+00:00

Hugo, that is a good find, theirs for some reason was disabled. I am guessing since she is an older employee, that way before my time, they were turning off everything except for two or three things in there, because all recent employee's I looked at, everything in there is enabled.

Unless it is a propagation thing, it still didn't work, but they also have everything except the first two disabled, so might require multiple things of the list that is left.
Jon Mercer 1,031 Reputation points

2022-05-23T17:55:13.74+00:00

Looks like it wasn't a propagation issue, since with just Outlook on the web, Outlook Desktop (MAPI), and Exchange web service enabled, it still was giving the same error.

I enabled the rest of them, and will see what happens. Most everyone else had them turned on.

[EDIT]

It was somewhere between one or all three of the last three. After enabling all three of them, and giving it a bit, they now can see other people's calendars. I am not going to mess with it since it works, so if others have this issue, and want to narrow down which it is, let us know here if you could.
Hugo Lemmens 81 Reputation points

2022-05-27T07:43:21.337+00:00

Well, if it ain't broke - don't fix it I would recommend. For what it is worth, my bets would be on de Exchange ActiveSync enabling. Glad at the end we found a solution.
Jon Mercer 1,031 Reputation points

2022-05-27T15:19:52.647+00:00

Exchange ActiveSync is my guess also.
Teraleenee 1 Reputation point

2022-06-02T18:02:12.577+00:00

Hello, JonMercer-8382, there are several answers to your question on different forum threads, so I will try to help you with helpful references.

The first hint - reason can be expired security certificates which should be renewed. The second - try to check if everything works on a different OS. This way, you'll make sure it is not a Windows glitch.

Updating/repairing Office can also be useful. Here you can find more details on each step of troubleshooting.

I also recommend using a NAKIVO backup for Microsoft 365 to make sure you can always recover after any system issues.
Jon Mercer 1,031 Reputation points

2022-06-02T18:07:16.783+00:00

Thanks, but none of those are of use. We figured out the issue a week or so ago. See the bottom of this conversation for the full reason, but basically it was a permissions issue in Exchange.
Ijaz Rexvi 1 Reputation point

2023-01-18T01:03:04.0466667+00:00

Hi, I've had the same issue, and tried everything as stated above. The user can access the shared calendar. on the desktop application from another PC, however on the specific PC is states "no connection" for all the shared calendars.

As it works fine on her personnel computer, I've re-installed office application and the issue is still persistent. I've also unchecked the "turn on shared calendar improvements" on the advance settings still with the no connection error.

any ideas or suggestions?
Jake Bloomfield 31 Reputation points

2023-05-25T09:07:55.89+00:00

Hi,

I am having the exact same issue with another user. I've made sure all of the Mail apps in the Admin centre for this user were enabled.. but no dice. Any ideas?

Cheers,

Jake
Daro Chong 0 Reputation points

2025-12-05T02:33:57.04+00:00

I just faced the issue and seems solved with the following command

Troubleshooting steps:

Run PowerShell to reset affected user's EWS:

Install-Module ExchangeOnlineManagement -Force

Import-Module ExchangeOnlineManagement

Connect-ExchangeOnline

Set-CASMailbox -Identity ******@xxx.xxx -EwsEnabled $false

Set-CASMailbox -Identity ******@xxx.xxx -EwsEnabled $true #This will reset the EWS status

Set-Mailbox -Identity ******@xxx.xxx -ApplyMandatoryProperties

The changes on the mailbox might take up to 24 hours to take effect

Answer 1

Hugo Lemmens 81

Hi Jon,
hoping this one will work for you too
Came across one post which suggested to make sure EWS was enabled for that account. (yet another acronym Exchange Web Services).
Found the location where to toggle it on/off
MS 365 Admin portal/user/ and our problem has been resolved.

Jon Mercer 1,031 Reputation points

2022-05-24T00:30:29.057+00:00

I am going to accept yours as the answer, because it got me in the right area, and I can't as far as I can tell mark my own comment as the answer. See below for what I ended up doing.
Yang Cheng 0 Reputation points

2023-07-19T18:16:59.2+00:00

Just wanted to say that we were dealing with this issue as well and enabling EWS fixed the issue. Greatly appreciated it.

Answer 2

Faery Fu-MSFT 19,836 Moderator

Hi @Jon Mercer ,

Welcome to our forum!

I have tried reproduced your scenario, and l get the following screenshot:

To fix it, go to the Send/Recive Tab, click work offline, click work offline again, it prompt for a password, then reconnect again

If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

Jon Mercer 1,031 Reputation points

2022-03-25T15:33:09.19+00:00

Tried that, it showed it went offline, gave it a bit, and clicked on it again, and it eventually showed it was back online, but never asked to put in a password. Calendar still shows as no connection.
Jon Mercer 1,031 Reputation points

2022-03-28T19:35:18.823+00:00

As an update, I quit out of Teams, went in to Credentials Manager, and removed the password for the Outlook account. Restarted Outlook, and put it in to Offline mode, waited a bit, and then put it back, and it still is not asking for a password. The calendar works fine with shared accounts she has added to Outlook, just not her personal account. It is though possible it is pulling a password from the SSO that is setup with office that it pulls from AD through Azure AD Connect.

It does work fine in OWA though, so it is an issue with Outlook.

Hoping for another option here, but am thinking about going with the scorched earth option, and rename the Outlook folder with all the OST's, and run the Office scrubber, and reinstall Office, and see if rebuilding everything fixes it. Rather not do this, since it takes a while to rebuild their Outlook.
Faery Fu-MSFT 19,836 Reputation points Moderator

2022-03-30T09:40:10.047+00:00

Hi @Jon Mercer ,
Is there any update on this thread?
If the issue resists, you can try to chage the 'default' permission on a single Calendar to 'Reviewer' via right-click on calendar > permission > add. set the permission level to "Reviewer", then check if there will be improvement.
Jon Mercer 1,031 Reputation points

2022-03-30T15:16:48.51+00:00

Just to ask, you did read my thread that you replied to that said as an update?

Where do I right click on calendar?

If I right click on my calendar, I don't have a permissions option.

Is this issue due to some type of permissions setting in the users Outlook, since it works fine in OWA, so it isn't an Exchange permissions or such issue, and it isn't due to a group policy, since it only happens to one person.
Faery Fu-MSFT 19,836 Reputation points Moderator

2022-03-31T07:30:07.64+00:00

Hi @Jon Mercer ,
I'm sorry that make you misunderstand me, the "right click on the calendar and select properties" I mentioned refers to letting the owner of the calendar set permissions in his outlook client

Is this issue due to some type of permissions setting in the users Outlook, since it works fine in OWA,

From your description, it works fine in OWA, it means the issue may be related to the Outlook client synchronization. Given this case, try the following troubleshooting:

1.Go to File > Account Settings > Account Settings, click change, more settings, advanced tab, uncheck Download Shared Folders. After that restart Outlook. Observe if the problem reoccurs.

2.Turning off the Cache Exchange Mode to resolve it, go to File > Account Settings > Account Settings, click change, uncheck Use cached Exchange mode to download email to an Outlook data file

If your issue has any update, please feel free to post back, and I would continue to research it with you.
Jon Mercer 1,031 Reputation points

2022-04-05T17:10:40.293+00:00

I tried both of those.

Did the first one, restarted Outlook, same issue.

Did the second one, restarted Outlook, same issue.
Ka Ho Chan 1 Reputation point

2022-07-04T09:51:47.01+00:00

I have the same issue due to removed some outlook credentials in the credential manager.

my resolution is change the password in the OWA web portal and then wait for the password changed box in the Outlook.
after re-typed the new password, the credential is rebuilt and I can read the shared calendars in my outlook client now.

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No Connection Error When Accessing Other Users Non-Shared Calendar Outlook 365

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