I have the same problem. I had a project on standby that I just started over.
I was with version 2.1.95 and everything was working fine.
When I updated to the last version, the “approved reservation” emails and “registration confirmation” emails stopped being sent.
By downgrading to the old versions I saw that the problem of sending emails starts with version 2.2.0
I applied the correction in the eme_mailer.php file but it does not solve the problem.
When I look in “Cleanup action” the messages are in the mail queue.
When I revert to V2.1.95 everything is working normally again.
What has changed between 2.1.95 and 2.2.0?
Can you help me to solve this problem.
The problem you’re describing is not related to the initial question at all, please open a new thread for this.
Also: if the mails are in the queue (which means you have queueing activated), you need to configure the queue send options (see “Scheduled actions” submenu).