Vultr vs DO for discourse

SMTP issues, can you elaborate?

Often the provider will block SMTP ports by default and you must often verify your identity (often providing government ID) to unblock them.

It’s possible they may have customer location restrictions but in any case file a support ticket with them.

Then you are usually free to use any third party email service.

I use Scaleway and Elastic email. No issues but new customers will need to verify identity to use email ports.