Outlook log in problem

Question

Outlook log in problem

Pavol 0

Hello,

Generally I'm having trouble signing into Outlook via a web browser.

A customer sent me a link to schedule an appointment, but after clicking the link and clicking sign in, I get an error window.

I have tried different browsers, I use Win10.

UTC Date: 2025-08-04T09:21:54.289Z
Client Id: ****REMOVE PII****
Session Id: ****REMOVE PII****
Client Version: 20250725003.04
BootResult: fail
Back Filled Errors: None
err: Error: 440
esrc: StartupData
et: ServerError
estack: Error: 440
    at Object.s [as createStatusErrorMessage] (https://res.public.onecdn.static.microsoft/owamail/hashed-v1/scripts/owa.bookwithmeindex.cf2b603d.js:2:63629)
    at https://res.public.onecdn.static.microsoft/owamail/hashed-v1/scripts/owa.bookwithmeindex.cf2b603d.js:2:87120
st: 440
efe: VI1P195CA0042

1 answer

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Answer 1

Mia - Tr 3,955 Microsoft External Staff Moderator

Hi @Pavol,

Thank you for posting in Microsoft Q&A Forum.

Please understand that our forum is a public platform, and we will modify your question to cover your organization domain name in the description. Please notice to hide these personal or organization information next time you post error or some information to protect personal data.

Regarding to your description, could you please share a few more details?

1 - Has this error occurred before, or is this the first time you're experiencing it? Have you successfully signed in to Outlook on the web previously?

2 - What type of account are you using to open the scheduling link (e.g., personal, business, education)? If you're using a business account and you're an end user, you may want to ask your organization's admin to check your access permissions in the Exchange Admin Center. They can verify whether your account has access to Outlook on the web using the guidance shown in the screenshots below.

User's image If Exchange Web Services is not enabled, please ask the admin to enable it and wait 5–10 minutes for the service to sync before trying again.

3 - Is the scheduling link you received similar to the Bookings link shown below? User's image If so, when you click the link, do you see a sign-in prompt like the one in the screenshot? Which sign-in method did you choose? If it doesn’t look like that, could you describe what you see more clearly?

4 - Have you tried opening the link in an incognito/private browser tab or clearing your browser cache? Do other apps (like OneDrive or Excel) show similar errors when you sign in with the same account, or is it only Outlook? Have you tested the link on a different device (e.g., mobile phone) to see if the issue persists?

In the meantime, could you ask the customer to describe how they created the appointment link? It would also help if they could resend the link or test whether others are experiencing the same issue.

Thank you for your time, I'm looking forward to your response.

If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".

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Pavol 0 Reputation points

2025-08-04T10:46:15.9466667+00:00
Hello ,

thank you very much for fast response.

Here are my answers:

It has occured before, I have never signed in to Outlook on the web.

I have business acount and I am only single person company, so I'm my admin :) I have verified whether my account has access to Outlook as you wrote, it hasn't. But after changins those setting the result is the same.

I tried incognito mode, outlook doesn't work. Excel and other apps works online.

I'm not able to test it on different device now.

I can't disturb my customer with that kind of my issues.
Mia - Tr 3,955 Reputation points Microsoft External Staff Moderator

2025-08-07T09:06:45.0566667+00:00
Hi @Pavol,

Thank you for your reply.

From what you've shared, I'd suggest a few troubleshooting step which may help:

Please try signing in using both the New Outlook and Classic Outlook desktop versions (if available) to confirm whether the issue is specific to the web version.

You can try to sign-in directly via Outlook on the web to determine if the issue persists across different access points.

You can verify TLS settings in Control Panel by:

Open the Control Panel on your computer.

Go to Network and Internet > Internet Options.

In the Internet Properties window, click the Advanced tab.

Scroll down to the Security section.

Make sure the boxes for TLS 1.2 and TLS 1.3 are checked.

Click Apply, then OK to save the changes.

Restart your browser and try signing in again.

If all the above checks are successful but the error still occurs when accessing Outlook on the web, it’s likely a backend issue within your tenant. In that case, I recommend raising a support ticket with Microsoft Technical support team. They can provide a more direct and effective solution for your case. They can perform a session to investigate the situation, they can escalate it to a specialized team for deeper analysis.

The Global Admin should create a service request with Microsoft Support to get advanced technical assistance and dianogsitc. For detailed instructions on how to get support, please refer to Get support - Microsoft 365 admin | Microsoft Learn.

As a forum moderator, we don't have access to the detailed logs or backend systems needed to troubleshoot this effectively due to privacy and security constraints. For that reason, the most efficient solution would be to contact Microsoft's support team directly.

Thank you for your time, if you have any further questions or concerns, please don't hesitate to let me know.
Pavol 0 Reputation points

2025-08-07T11:22:19.0166667+00:00

Hello,

After several attempts, I managed to switch from classic Outlook to the new one. I´m not sure but it looks like there is some problem with my domain provider.

I can see the problem also if I open Outlook on the web. Now it works, but there are only few emails. It looks like I have two different types of email accounts connecting with microsoft 365, with same email address. Is it possible?

I would like to make things right.
Mia - Tr 3,955 Reputation points Microsoft External Staff Moderator

2025-08-11T12:54:46.1066667+00:00
Hi @Pavol,

Thank you for your reply and for sharing more the information.

Regarding your concern about the domain provider, without specific details, I'm not sure to confirm whether this is the root cause. If you’re seeing errors related to domain configuration (e.g., DNS or MX record issues), I recommend checking the domain setup in the Microsoft 365 Admin Center > Settings > Domains > Ensure the records points to Microsoft 365’s mail server.

Alternatively, your domain provider’s support team can assist with verifying DNS settings.

And about "It looks like I have two different types of email accounts connecting with microsoft 365, with same email address. Is it possible?"

In my experience, yes, it is possible to have to different types of accounts associated with the same email address in Microsoft 365 in case that your tenant is in hybrid or misconfigured environments. For example:

One could be a Microsoft 365 (cloud icon) account.

The other could be an on-premises Active Directory account synced via Azure AD Connect.

To double check, in Microsoft 365 Admin Center, you can navigate to Users > Active Users and check if your email address is listed multiple times or associated with different account types (e.g., user mailbox, shared mailbox). For the hybrid account, you can filter and find the sync status by follow this instruction below:

1- In the Microsoft 365 Admin Center > Users > Active Users > Choose columns

2- Enable the sync-status

3- If the account is sync via Azure AD Connect, you can see the table icon as the picture below

And to ensure everything config as smooth as you mention, I'd recommend you raise the support ticket to Microsoft Technical support team. They can perform the remote session if needed to check and clarify your issue. As forum moderators, we don’t have access to the detailed logs or backend systems needed to troubleshoot this effectively due to privacy and security constraints and can provide you the information based on the public resource document. Therefore, the most efficient solution would be to contact Microsoft's support team directly.

For detailed instructions on how to get support, please refer to Get support - Microsoft 365 admin | Microsoft Learn.

I hope this information helps. If you have any further update, please don't hesitate to let me know.
Mia - Tr 3,955 Reputation points Microsoft External Staff Moderator

2025-08-14T07:36:44.3633333+00:00

Hi @Pavol,

Good day and I hope you're doing well.

It has been a while and I wanted to check in to see how things are going with this issue. Have you encountered any difficulties with your account, or any difficulties when trying to reach Microsoft’s Technical Support teams? If not, have you received any updates or information from them?

Thank you for your valuable time.
Pavol 0 Reputation points

2025-08-16T09:16:28.4066667+00:00

Hi @Mia - Tr at first, thank you very much for your effort.

I can say that I'm able to open outlook via browser, what is a progress. The problem still is that there are only some email from the past, but I think I know why:

I tried to connect/define my domain with my microsoft 365 account few months ago. It was successful, but after this operation, I didn't see none of my emails in my email box. Therefore after few days I decided to cancel connection between my domain and MS365. The messages which were received during those days are now visible in outlook in browser version.

Is there any way how unite both "email boxes"? I use IMAP for outlook app.

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Outlook log in problem

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