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As of this week, modern auth on the Outlook mobile app (on iOS and Android) is no longer authenticating with modern authentication to an Exchange 2019 server which is configured with hybrid modern authentication.
This was previously configured and has been working for about a month without issue. It was configured based on this guide: https://learn.microsoft.com/en-us/microsoft-365/enterprise/configure-exchange-server-for-hybrid-modern-authentication?view=o365-worldwide
The native mail app on iOS does not appear to have issues authenticating with modern auth. Additionally, OWA, MAPI, ECP and other Exchange services which use modern auth are still able to authenticate.
Using the Microsoft Connectivity Analyzer, Outlook Mobile Hybrid Modern Authentication Test, I receive the following error message on the "Analyzing the services listed for the user on the Outlook Mobile Autodetect endpoint." step:
We didn't find the Microsoft 365 service in the response from Autodetect. The user may not be synchronized to Microsoft 365.
I can confirm that the users are fully synchronized into Microsoft 365/Entra ID.
I'm looking for suggestions on items to check or any news of issues from Microsoft's side regarding the authentication flow through their systems.
This must be resolved promptly to complete migration to modern auth and improve security of our environment by removing basic authentication.
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FYI this is a KNOWN issue that MS is now investigating under the following ID in the o365 Admin Service status portal - EX918851.
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Monday morning and Outlook Mobile is working again.
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Outlook mobile working again but still can't add NEW accounts using modern auth. Original issue not fixed.
This appears to be a separate issue.
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Thanks for posting your question in the Microsoft Q&A forum.
Based on your description, I need to shorten the scope of the question :1.Is Outlook working fine for you on your PC?
2.Are other users experiencing the same problem?
3.Does this problem occur when logging into Outlook on another phone?
Your answer is very important to solve the problem, thanks for the support and understanding.
Edit: duplicate response delete.
According to your description, you can use Outlook normally on your PC. The problem lies in the Outlook mobile connection.
In order to better solve your problem, it's suggested to post your issue on this dedicated forum for Outlook for Mobile for more professional help.
If my answer is helpful to you, please mark it as the answer so that other users can refer to it. Thank you for your support and understanding.
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Outlook on the PC works fine for us. It's affecting users on iOS and Android using the Outlook Mobile app. The native Mail app works fine.
After removing the app and reinstalling we're now unable to add an email account on our Exchange 2019 through the Outlook Mobile app. Just says "Unable to sign in" when if you deliberately get the credentials wrong it recognises that they're wrong.
Similar situation @ADAM QUINCEY that only seems to effect Outlook Mobile.
It seems all other ways of accessing email works, apart from via the Outlook Mobile app.
Can you access via native Apple mail app?
@Bruce Jing-MSFT Thanks for the information, it does appear to be an issue with the Outlook Mobile app Autodetect service. I suppose it's not possible for you to move this thread to that forum?
Unfortunately, since I don't have access, I can't move the post to the Outlook mobile forum, I hope you understand. If my answer is helpful, please mark it as an answer.
Hello everybody,
since that night we are facing the same issue.
Native Mailapp working, but Outlook Mobile doesn't.
Other mailclients are not affected. The Remote Connectivity Analyzer does not show an error.
Did you find the problem?
Best regards,
Stefan
I have been in contact with several support teams and have not yet resolved the problem.
I have discovered that the issue likely lies with the Microsoft Cloud Autodetect service.
A way to test the Autodetect service is with a web request crafted in a similar way in which the app does. Like so:
$encodedEmailAddress = [Convert]::ToBase64String([Text.Encoding]::UTF8.GetBytes('user@contoso.com'))
Invoke-WebRequest -Uri 'https://prod-autodetect.outlookmobile.com/detect?services=office365,outlook,google,icloud,yahoo&protocols=rest-cloud,rest-outlook,rest-office365,eas,imap,smtp' -Headers @{'Authorization' = "Basic " + $encodedEmailAddress} -UserAgent "PowershellRuntime" -Method GET
Then another to the dev version of the same service:
Invoke-WebRequest -Uri 'https://dev-autodetect.outlookmobile.com/detect?services=office365,outlook,google,icloud,yahoo&protocols=rest-cloud,rest-outlook,rest-office365,eas,imap,smtp' -Headers @{'Authorization' = "Basic " + $encodedEmailAddress} -UserAgent "PowershellRuntime" -Method GET
The response should be nearly instant and will provide autodiscover service information as well as Oauth authentication information.
In my case, the prod service hangs for minutes and eventually returns an incorrect response. However the dev service instantly returns a correct response.
This indicates to me that something has changed on the prod Autodetect service and is incorrectly configured.
This is completely in the hands of the Microsoft mobile app services team. I am still waiting for their support to confirm and resolve the issue.
Watching with interest as we have a similar issue.
At 00:41 this morning we are experiencing the exact same issue with no changes made.
We have reached out to MS support, but no response as yet!
I just ran those scripts @ConsequenceWestern97 & both our prod and dev responded straight away, so not sure we have the same issue, although we are experiencing a similar issue!
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Hello!
I have the same problem. From this night Outlook for iOS and Android doesn't work. All our employees cant recieve mail. No updates of the mails. After deleting the account from mobile Outlook i can't add it again.
On Outlook for iOS error "Unable to log in".
On Outlook for Android - "An error occurred during authentication Please try again."
Two times when we tried to add an account to mobile Outlook, we could do it, but mail was old, from yesterday without new mail messages. Our mail server is Exchange 2019 CU12, not hybrid. Through another mail client over imap/pop/smtp all works fine. With OWA also no problem. With Mail app on iOS with Exchange all works fine including sync with Mail, Notes, Contacts, Calendar. And i see all new messages from midnight. Сertificate is valid. Autodiscover works fine, with Outlook app on windows no problems with account add over Exchange. Problems only with Outlook app for iOS and Android.
We have not found a solution to this problem, so for now we recommend that employees use OWA.
what time did this start for you @Anonymous ?!
What time did this start @Anonymous ?
Outlook only shows emails that were received yesterday. Today's emails are not visible in the app.
Outlook only shows emails that were received yesterday. Today's emails are not visible in the app.
if you go into OWA and got to SETTINGS cog (top right corner)>OPTIONS>GENERAL>MOBILE DEVICES, what does it say the last contact time is?!
Last connection from Outlook was 11:07pm GMT, 2024-10-25.
My colleagues last connected from mobile Outlook at 12:55am GMT, 2024-10-26
From this time maybe problems started.
Microsoft sent an email about an hour ago saying theres an investigation ongoing their end.
EX918851: Exchange Online Service Health Incident
But the problem is that we don’t use Exchange Online, we have our own server with Exchange 2019.
Its just a typo. It states ONLINE if you read the email it says ON PREM. You can check the status via the 365 Admin portal HEALTH>SERVICE HEALTH.
That alert status ON PREM!
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We’re experiencing the same issue with Outlook mobile for iOS connected to Exchange on-premises. The problem began on October 25, 2024, and there’s still no resolution from Microsoft. The native iOS email client, however, continues to work without issues.
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We’re facing the same problem with Outlook mobile for Android (not tested on iOS) connected to Exchange on-premises (2019). The problem began on October 24, 2024, the only thing different in my scenario, is that we've one user can still login and logout whenever he wants, and he receive emails on the outlook android app.
This problem, is really making a disaster, because all uses use that app.