New issue with multiple Outlook accounts and containers

[vtgroup]

I use Firefox containers to manage multiple email accounts.  Two of them are outlook.office.com URLs, but the login_hint in the query string is different, so the URLs are different.  This has not been a problem this entire year.  However, starting this week, I can only seem to get one of them logged in at a time. 

While I manually choose to open URL 1 in Container 1, a new tab opens for Container 2 to continue the login.  Same behavior both ways.  I can no longer have two tabs/containers logged into my two Microsoft accounts.  I've even tried changing the second base URL to use outlook.office365.com, hoping that was enough of a distinction to keep them separate, but even that's got the problem. 

I thought each container was completely separate from the rest?  If so, I'm not sure what's going on internally. I've also done "Clear storage and cookies" multiple times, and deleted and recreated the containers, but that doesn't solve the issue.  I'm back to using all my accounts but one in Firefox, and my other Outlook account in Edge. 

Any ideas?  And if there's more correct place to post this, please let me know.  I'm new to the Mozilla site.

[siffemcon]

If you enter a URL in the address bar on your home page, does it open there or in a new tab?

[vtgroup]

This issue actually mostly resolved itself on Friday. I didn't do anything but retest later in the day and it worked. I'm not aware of a Firefox update, so something must have changed at office.com?

However, I just tried logging out of one account in one container and logging in again.  Everything seemed to work correctly through the user/pass and MFA steps, but when the mail page should show, I was returned to the user/pass page (still in the correct container, though, which is not what was happening last week). 

I did figure out though that I was always answering "Yes" to "Do you want to stay logged in?", and when I tried answering "No", it worked correctly.

I don't have time to test more thoroughly, but plan to this week.  I think the Network tab in the Developer Console might show something between HTTP return statuses etc.

[rahvee]

I have the same or similar problem. Multiple containers for outlook.office.com. Starting yesterday can't login to multiple accounts. In one tab it says wrong password; in another tab it goes through the motion of logging in and then says "You signed out of your account." which makes me think the containers are not fully isolated. I fully cleared my browser cache and history, then was able to login, but the problem came back next morning.

[vtgroup]

It's still working again for me with no issues.  But I haven't had the courage to try logging out/in, as I don't want it to break again if it's not truly fixed.  The only advice I can offer is my suggestion above about "Do you want to stay logged in?", as I did test that, and the answer did seem to change the behavior.

Once my session expires and I'm forced to re-log in, I'll reply back if it's still fixed or I need to dig deeper.