Exim4 failts to use smtp.office365.com as its smarthost

[Andrew Hodgson]

ael wrote:

>On Fri, Aug 04, 2023 at 07:29:18AM +0200, Sébastien Hinderer wrote:
>> Here is the relevant excerpt from mainlog:
> 
[...]
>Well, I am not sure what is going on in that log, but plain exim does not support oauth which is needed to send to office365.

I don't know if this will work in your case, but I ended up setting up Exim posting through M365 using a static IP and a connector. If you don't have a static IP you can authenticate based on the certificate CN that Exim presents when connecting as well, I've done it both ways. This means no SMTP authentication is required.

Thanks.
Andrew.