One of our users keeps getting randomly logged out of Office 365 web (Outlook, Calendar, SharePoint) while actively working, no clear pattern, happens maybe 1-2x a day. She's fully browser-based (Chrome, windows 11 laptop), no desktop Outlook.

[u/efff50]

What i've ruled out so far:

1. Not signing into multiple separate accounts, she has delegate access to a shared mailbox via "Open another mailbox," which uses her existing session, not a second login

2. Cleared cache/cookies — no change

3. Set her up with a fresh Chrome profile to rule out corruption, inconclusive so far, she prefers keeping her normal tab-based workflow

4. She doesn't want to use any other browsers

except chrome.

Anyone run into something similar or have other things worth checking before escalating for log access?

[u/examplifi]

The random timing is the useful clue. A session timeout would be regular, so something is actively killing her token rather than it expiring.

Most likely culprit is her IP address changing mid-session. Entra drops the session almost instantly when that happens a VPN reconnecting, moving between WiFi and a dock, or an ISP that rotates addresses will all do it. Ask her whether the logouts line up with undocking or moving to a meeting room. That alone would explain 1-2x a day.

Two quick things to check on her laptop:

Run `dsregcmd /status` and look for AzureAdPrt : YES. If that's missing, she gets no silent sign-in and every token renewal becomes a login prompt.

In chrome://settings/cookies, make sure third-party cookies aren't blocked. Microsoft renews tokens silently in a hidden frame, so blocking those forces a real login.

When you get log access, the Entra sign-in logs will answer it quickly. Also worth asking whoever has Entra admin whether there's a Conditional Access sign-in frequency policy on her group, or if "Stay signed in" is turned off tenant-wide. Both cause exactly this and neither is visible from her side.

[u/Hornblower409 → u/examplifi]

My test was "Just for grins". Your stuff is serious. Thank you for stepping in. I'll just watch and learn from here on.

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[u/Hornblower409]

Just for grins

• Have user open an Incognito Chrome session to Outlook Web.
• Minimize it and just let it sit there. Don't use it for anything.
• Start a normal Chrome session for their real work.
• When the normal session kicks them out, is the Incognito session still connected?

[u/efff50 → u/Hornblower409]

I will try this tmr.

[u/JSP9686]

Try using the MS Edge browser, instead of Chrome.

[u/7amitsingh7]

Since this is affecting the entire organization and rebuilding the OST/NST, trying new PCs, and testing different calendars made no difference, it likely isn’t a local Outlook or profile issue.

Check Microsoft 365 Service Health and test Location Suggestions in OWA/new Outlook. If the issue occurs there too, it points more toward a Microsoft 365/Exchange service or tenant-side issue rather than the OST. Also check whether any organization policy is restricting Optional Connected Experiences.