myVesta

In order to do that, you will need to modify both nginx and apache2 config files.
Unfortunately, I never did that, so I can't tell you what exactly you need to modify.

Check /var/log/exim4/mainlog
A hundred different reasons can be.

Yes.
No need to keep mysql port open if you are not using mysql from some remote host.
It's better to keep it closed, better for security.

Try this - viewtopic.php?f=20&t=36

If your exim is up, there is nothing to worry about.
You can see what was the problem by looking that log: Then you can erase panic log with:

- I have in my cloudflare DNS installed SPF, DMARC & DKIM under my hostname domain only. But my hostname is web01.<DOMAIN>. So its not installed on web01.<DOMAIN> Can this be a problem? Probably this. So, instead of adding "_dmarc" you should add "_dmarc.web01" BTW, check wh...

mod_rewrite is enabled by default as Apache module.
It's not related to PHP.

1. wp-hide - it's not related to myVesta, it's probably due jump to php7.4

2. not sure, never used wordfence

3. it's just info table, use server hostname and make sure you generated SSL for server hostname WEB

try login from browser with 0 addons, and see...