I don't have an AD account without Multi Factor Authentication as well, so I could not make it work for my own user either.

I would suggest you do as Henrik Gruß did here. You can make a gmail dummy account, that is what I did.
Send mails using Google Mail

The important part to make it work is this
https://myaccount.google.com/u/0/lesssecureapps

The previous off course is for notifications on execution packages, but it also works for this. Here is my setup.

Here is the notification mail I got.

I revisited this and my IT colleges is not happy about setting up a Gmail account for this. My suggestion was to set up a simple SMTP server on the same machine as the ODX is run on, but that is not acceptable solution either.

The notifications from Excecution packages works. There we only specify server, port and from email. Not user name and password. I have checked Allow Invalid Certificate.

Our SMTP server is an on-prem Exchange 2016.

Is it possible to get this fixed in the near term?

Hi again!

In the 20.10.17 release this should be fixed:

10309: ODX Alert mail server tries to authenticate empty user

• The application will now use the proper format for situations without any user/password authentication. E.g. Situations on internal SMTP servers.

Now it is doable to send a test notification through our on-prem smtp-server without username and password. But it is not doable to save the change because I get an error message when clicking OK saying User name is not specified and Password is not specified. :(