myVesta

I think that you can change MaxRequestWorkers is set in /etc/apache2/mods-available/mpm_event.conf After that restart apache. Anyway, this is very unusual. You are either under some http flood attack, or your PHP application is simply holding process for infite time? What are the values for pm.max_c...

Unfortunately, not. Vesta is using MD5 hash function for passwords hashes, and cPanel uses (I think) SHA-256 algorithm. Both algorithms are one-way-only, so there is no way to get decrypted value (in order to crypt it again with MD5 algorithm). You can only set old passwords manually, if you know th...

Check file /var/log/php-mail.log
Maybe you can see sent mails there.
If you see them there, confirm me, so we can continue.

Then something other is problem.
Do you see anythinng in error log for that domain?

Hmmm, you are right, I didn't see it. Maybe in some specific situation DNS on our servers can be used for PTR for some IP pool, but that's not definitely scenario in which myVesta is commonly used. Probably it's there because Bind9 can do it, but in some very other scenario... when your server gives...

Maybe somehow they kept old template.
Nginx proxy template must be hosting-webmail-phpmyadmin or hosting-legacy.
Trust me

You can't set PTR record in hosting panel. Your datacenter is probably providing an interface for that - in the same 'panel' you can cancel server, shut down server, buy more servers, and other datacentar related stuff. PTR record should be equal to your server hostname, and yes, it should be FQDN, ...

That's not deface.
Please read viewtopic.php?f=7&t=37

Can you make the screenshot of "deface" ?