I've recently experienced being unable to send emails via my hotmail / outlook email account to other addresses.
It all started after enabling 2-factor authentication on the account, then disabling it again. I had a suspected breech, due to a Microsoft community email problem....
Now, I can only post emails to other "hotmail" accounts, but to no others, except it I use the web interface.
Any ideas upon what's wrong, and how I can fix it ?