In OJS 3.1.1-2 does port 25 without TSL/SSL work

I did an upgrade test from OJS 2.4.8 to OJS 3.1.1-2. For the OJS 2 the email works fine. But for OJS 3, nothing gets out.
in OJS 2
I have an exchange server on port 25 of our institution. with smtp_auth = LOGIN option
But for OJS 3 there are only ssl and tsl possibilities, for smtp_auth.

Is it possible to have the email working without ssl/tsl in OJS3?

Thank you so much!

Have you tried to copy all the whole email config from OJS 2 to OJS 3?

Best regards, Primož

Yes, this is what I did actually. But … It didn’t work.