Outlook 365 continuously asking for password in July 2026

Question

Any definite insight to the "Outlook 365 continuously asking for password" issue:

Problem

Randomly (almost every day), Classic Outlook asks for the IMAP password although it is

correct. If Cancel is clicked, Outlook remains stuck in Sending/Receiving indefinitely.

Infomaniak webmail continues to work normally. Restarting Outlook one or two times,

or rebooting Windows, eventually restores operation.

What has been ruled out

• Windows 10 and Windows 11 (same behaviour)

• Multiple Office reinstalls

• Several Windows reset/recovery operations

• Large/corrupt OST (only ~48 MB)

• Norton Antivirus (Safe Mode showed same issue)

• Incorrect password (webmail always works)

• Internet connectivity (browser remains fully functional)

• Incorrect IMAP/SMTP settings

Debugger findings

A full Outlook process dump was analyzed with WinDbg. The dump shows Outlook

hanging inside Microsoft's IMAP synchronization components (PSTPRX32.DLL and

OLMAPI32.DLL). The main Outlook thread waits indefinitely for an IMAP worker thread

to stop, explaining the endless Sending/Receiving state and the subsequent password

prompt.

Most likely causes

1. Bug in Classic Outlook's IMAP engine.
2. Compatibility issue between Outlook IMAP and Infomaniak IMAP.
3. Outlook profile corruption (considered less likely after years of reinstalls).

Not worth repeating

• Reinstalling Office again

• Reinstalling Windows again

• Repairing Office again

• Changing passwords repeatedly

• Further IMAP setting tweaks

• Repeating Norton or Safe Mode tests

Answer 1

Hi OAC,

Welcome to Microsoft Q&A forum. 

Based on your description, this does not appear to be a typical incorrect password, IMAP settings, antivirus, OST, or Windows profile issue. Since Infomaniak webmail works normally with the same credentials, the password is unlikely to be the root cause.

The fact that Classic Outlook gets stuck in Sending/Receiving, along with the dump showing Outlook waiting inside the IMAP synchronization components, suggests that the password prompt may be a secondary symptom after the IMAP sync process becomes stuck.

At this stage, repeating Office repair, Windows reset, password changes, Safe Mode testing, or further IMAP setting adjustments is unlikely to help. The best next step is to contact Microsoft Support and provide your Outlook build number, Windows version, Infomaniak IMAP details, and the WinDbg findings related to PSTPRX32.DLL / OLMAPI32.DLL for deeper product-level investigation.

You can contact Microsoft Support using the steps below:

• Go to Contact Us: Microsoft Support Contact Us
• Click Show expanded list of products
• Select Outlook > Get Home support
• Type Outlook live chat in the search box, then select Get Help > Contact Support
• If you cannot sign in to the affected account, use a different Microsoft account to access support options
• Under Products & Services, select Other Products > Outlook, then choose Chat with a support agent via web browser

Please note that this is a user-to-user support forum. Moderators, contributors including external Microsoft employees cannot directly intervene in Microsoft product features or access back-end systems. Our role is limited to providing technical guidance on reported issues, requests, or ideas only.

Thank you for your understanding. 

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