We have an issue for a long time that I don't know to fix (mfl version 2.4.24. server runs PHP 7.4). Some emails are just not sent (Or rejected by some providers?). For example, we have severe problems with GMAIL and GMX. Personal domain emails, on the other hand, work fine. So, I'm pretty sure it is not exactly a mlf issue.

One strange thing: We have always 3 sender addresses in the email header. Two are generic server addresses like forum@fh6f56h4.server.com. The last is the correct forum email.

Can I somehow log the emails sent by mlf? This would make troubleshooting easier. Can I somehow change the settings so, that only the standard forum email is included in the header?

mlf runs on good quality shared hosting (all-inkl.) I assume no serious issues there.

Any ideas would be very much appreciated.