Microsoft 365 lost connection - not Oauth2 option


We lost connection to Microsoft 365 in our company on eM Client 8, due to Oauth2 option not being available.

We paid for the eM Client and we need a solution to make it work.

No app update available.

Thank you.


Btw, as pro user with bought licence, why I cannot use any other support then community forum?!

eM Client V8 does support Oauth2 and has done since V7.

Have you tried removing and re-adding your account via the automatic email wizard ? If you haven’t suggest to do that as would more than likely resolve the problem.

If still a problem, do you see any error messages appear when trying to receive or send email.

Also the latest versions of eM Client for PC and Mac are available via the Release history page if you want to check anytime.

Also as you bought a Pro license you have eM Client Pro VIP support via the following page Support | Remote Assistance | License Manager | eM Client

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Is this the message you receive? If so I removed the account and re-added and it seemed to fix it. Good luck!

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Thanks a lot for reply!

Unfortunately re-adding account does not work.

In the configuration I can set only encryption method (TLS), but not authentication method.
As per googling I am the only one with this issue and Microsoft 365.

Microsoft 365 completely disabled basic IMAP authentication, so without being able to choose Oauth2 I cannot log in.

Automatic configuration does not help as well.

Reg. support, we have bought licence for our company from our main software vendor and we god licence keys, but the support needs some login which I do not have and I am unable to open ticket from the app. No very friendly if you do not buy directly on website imho.

Thanks a lot for reply!

Unfortunately did not helped :confused: basic IMAP authentication is disabled for good on Microsoft 365 and without being able to force it to use Oauth2 we are not able to use it and its impacting our business :confused:

Same for me. Deleted account and readded, issue still persists. Time to switch clients if these can’t be fixed. Any suggestions for one with a combined inbox for multiple accounts anyone?

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Is the Office 365 account part of a “Domain” ,?

Outlook or Thunderbird tested and working.
However when we have paid for the licence I would expect Em Client team to fix it long time ago, this change of complete disable of basic IMAP was announced long time ago.

I sent mail for the support, no answer…

Seems they care only about sale… :confused:

Yep, we run it on our own company domain.

However the service is provided by Microsoft 365 and even open source thunderbird does not have issues with recognising config.

Its still using for IMAP and for SMTP…

Yep, we run it on our own company domain

I believe there was a problem with adding a Office 365 acct “if it was eg: part of a domain or joined to a Domain” . This issue was updated / fixed in eM Client V9.

So I suspect this issue you are having could possibly be related to that. I don’t know if this was also updated / fixed in a later V8 of eM Client.

So try the latest version 8.2.1721 PC or 8.2.1687 Mac (if you haven’t already) via the release history page. Close eM Client before installing the update.

Thanks again for the answer.

Unfortunately no… We are on latest version and does not work.

I would understand not being able to configure it automatically, but the fact that I cannot simply choose Oauth2 even when the client have the code needed piss me off…

I wanted to support small developers from EU by buying the licence, but I can see it was a mistake. This approach to customer is red line for me :confused:

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but the fact that I cannot simply choose Oauth2 even when the client have the code needed piss me off.

You “don’t normally manually” choose OAuth 1 or 2 with eM Client as all of that is usually automatically done in the wizard with the token at the end of the wizard with Office 365 accounts.

So sounds like either eM Client V8.2 possibly still needs another update with Office 365 and Domains like was updated in V9, or there is something else you need to do locally in eM Client or the OS to make it work. Hopefully someone on this free forum can help you further.