I gave a try with 4.4.11 but this time I cannot send email at all - not even a “test email”, giving this error:
I think I will sooon die…
4.4.11 is not supporting PHP8… so it should still be 7.4. Do never forget to clear cache in between.
Sorry, can’t help yet with settings in Mautic 5.
If you haven’t set up queuing, it shouldn’t queue and send immediately. If it didn’t send, there is still some trouble.
However - first things first. You should really use some professional Mail Sending service like AWS SES or similar supported services. Sending via the hosting company is maybe fine for some tests, but never for serious mailings. You will run into problems with reputation, blacklisting and so on.
Have you considered to use some hosted Mautic offers where those kind of issues are not your issues anymore? 