After you successfully imported all Hestia mail domains into your Proxmox Mail Gateway, you might want to sync Hestia to PMG when you add OR delete a mail domain in Hestia as an allowed Relay Domain mail destination on your Proxmox Mail Gateway. Here’s the how-to!
https://blog.campodoro.org/?p=2395
Ps. If I cannot link blog-posts here, I can also copy-paste it. Cheers!