Mail through Office 365 SMTP just stopped working

Discussion of bugs in Seamonkey
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RDaneel
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Joined: January 19th, 2004, 2:43 pm
Location: Puget Sound, WA
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Mail through Office 365 SMTP just stopped working

Post by RDaneel »

... and I don't know if this is a MSFT issue, or a SM issue - so partly I would like to hear if anyone else is noticing anything broken with their Office 365 -based email(?).

I just noticed this last night after installing the latest (from 20220714) Build By Bill(tm) and trying to send an email: after connecting to smtp.office365.com with my usual settings (port 587, STARTTLS, OAuth2), I received a "login failed" error. Note that retries don't get any better, and the "Enter New Password" button in the error dialog doesn't actually give me a chance to do that. :(

So I immediately uninstalled and re-installed a SM from 2 days ago. but the behavior is the same.

I would think this is just a MSFT issue, but SM not handling the error dialog properly makes me wonder... and finally, OAuth2 has been working perfectly for me since March (both POP and SMTP with the Office 365 servers).
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mtalbot
Posts: 50
Joined: October 13th, 2015, 5:21 am

Re: Mail through Office 365 SMTP just stopped working

Post by mtalbot »

I just had something similar happen so it sounds like an MS issue. I suggest logging in to the web portal and checking your recent activity to see if they've tagged anything as unusual (They had for me) and blocked access until you confirm it was you (or you change your password).
RDaneel
Posts: 603
Joined: January 19th, 2004, 2:43 pm
Location: Puget Sound, WA
Contact:

Re: Mail through Office 365 SMTP just stopped working RESOLV

Post by RDaneel »

Wow, thanks, mtalbot! :)

Clearly, good ol' MSFT decided to make some key changes in their SMTP admin controls which apparently took effect on July 15... sigh.

But with your tip, I went to my "Microsoft 365 admin center", displayed Active Users, selected the one used for emailing, then picked "Mail" in the flyout that came up, and then I was [finally] able to "Manage email apps" - which allowed me to enable "Authenticated SMTP" (which presumably got disabled for some reason on July 15).

Then sending - still using my already set up and working OAuth2 in SeaMonkey - started working again immediately! :)

As a follow-on, I will say this was particularly user-unfriendly on Microsoft's part - I am subscribed to the emails all "account admins" get on Microsoft 365, but not a peep about this rather ugly "update"... I did, a few months ago, adjust the settings to only send me "important" notices affecting service, but I guess this one didn't make the cut. Grrr. :?
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