TB 38.5.0 - Outlook email SMTP setup

[BretMan]

Hello,

I have several Outlook.com email accounts working fine with TB's SMTP setting as smtp-mail.outlook.com. However one account, which I can receive messages but it won't send, gives me this Alert "An error occurred while sending mail. The mail server responded: 5.2.0 STOREDRV.Submission.Exception:SendAsDeniedException.MapiExceptionSendAsDenied; Failed to process message due to a permanent exception with message Cannot submit message. 0.35250:0D040000, 1.36674:0A000000, ... [Hostname=DM6PR12MB3466.namprd12.prod.outlook.com]. Please check the message and try again. ".

Outlook mail settings shows new SMTP settings should be: smtp.office365.com. At TB's Identity Settings>Settings>Outogoing Server (SMTP):, the window shows: Outlook.com (Microsoft) - smtp-mail.outlook.com. Clicking on that shows a pull down menu of 15 more to select from and most are the same one, smtp-mail.outlook.com, which are for my Oultlook accounts. I need to add or switch to smtp.office365.com in that menu list but I do not see how. I also need to change the port to 587. Maybe this will fix the TB sending issue on this account.

How do I do that?

Thanks.

[tanstaafl]

https://cknotes.com/office365-smtp-erro ... dasdenied/

"The Microsoft Office 365 SMTP server provided a wonderfully informative error message (sarcasm).

The clue in all of the above gibberish is the “SendAs” in “SendAsDeniedException”. It means you authenticated using one email address, but tried to send email using another email address for the “FROM” address. (i.e. you are “sending as” another person).

Your Office365 account may need to be setup to “Send email on behalf of another user”"

It sounds like you are trying to use a multiple identity in your Outlook account in Thunderbird, but need to register that email address using webmail so that the SMTP server doesn't reject it as a illegitimate From: address. If that's what's happening, the same type of problem will occur with Gmail if you use a different From: address (just need to register it in gmail webmail as an additional From: address), but they give a much better error message.

[BretMan]

Thanks tanstaafl.

I sort of understand what the problem may be. I went through the Outlook mail expanded settings and didn't see anything related to "Your Office365 account may need to be setup to “Send email on behalf of another user” ". I don't know if this has anything to do with it but my Outlook accounts are the free personal versions, not the paid business or Microsoft Teams ones. I think the non-free ones are Office 365 - however when I sign up for the free ones, they always start by giving a free trial period of the Office 365 which I let expire, which is where they all stand now.

The Outlook account with this issue used to work fine for a couple years, then stopped sending about 6 months ago. I even had login problems and it said I had too many Outlook accounts using the same phone number for verification codes, then a few weeks ago that issue went away. If I try to send a message that initiates from the Outlook mail account online, that sends it ok.

All my other Outlook mail accounts in TB are set up exactly the same except for the address name, and for Outgoing Server (SMTP), smtp-mail.outlook.com is used. I just thought to try switching it to smtp.office365.com on this problem account to see if that may fix it but I don't see a how to enter it in TB's Outgoing Server (SMTP) box.

Any suggestions?

[BretMan]

After many hours I stumbled onto the solution and it's working again, receiving and sending messages:

InTB's left pane (where all the email accounts are listed) scroll to "Local Folder" (the last one at bottom by default) R-click it then R-click "settings". That shows the "Account Settings" window. There, go to left pane agian > "Local Folder" and R-click "Outgoing Server (SMTP)" . Now you'll see the "Outgoing Server (SMTP) Settings" window, from which you can add or edit existing SMTP settings. Also, each one listed is specific to each individual email account in TB and you'll see which one when you click on them. Only edit the one specific to the email account you're trying to fix.

I first try to match the settings of the problem account with the the email accounts that are working Ok from the same email service (Outlook's), If that doesn't work, edit the settings for just the problem email account as per what the email service recommends - they may have been updated. For Outlook: https://support.microsoft.com/en-us/off ... 414e2aa040

Done.