I read this forum via email and I got the impression that email delivery is unreliable: for some posts, I did not get an email notification. This problem is not related to the recent server switch: email notifications have been occasionally lost since the switch to this forum.
I assume that this might be caused by an anti spam measure of my mail service provider: to increase the cost for spammers, email delivery is often rejected with a temporary error message ("please try again later"). As this is a temporary error, a conformant mail server should retry the delivery for some time. Maybe, the retrials are very limited for this forum's mail server (I have not yet observed lost emails from other mail servers).