How to use an smtp server in hestia

Hello, I would like help with the following.

In a previous report I commented something about smtp issues, now after a while I found a possible solution but I need help.

I manage several servers of my clients, in this case one of them has a server with cpanel and in another I have hestia, in both I had the problem that the messages did not go to gmail, that is until I bought another server to be the SMTP server ,
in this case I configured and redirected the domain to this smtp server,

when opening it from the cpanel mail administrator the message came out working correctly.

In the case of my hestia domain, I did the same configuration but it didn’t work. I don’t get the message, can you help me solve it? I don’t know if it’s because the domain ( must be linked to the root server, but the if it points to the smtp server.

should i configure something?

Gmail but mostly Microsoft are a big pain in… I’d recommend using a a dedicated SMTP relay service (which is build right into HestiaCP) f.e. SMTP2GO works great (and they have a free tier with a max of 1000 e-mails).