Unrouteable address - external inbox

Hi everyone,
one of the site I’ve migrated to my cloud is returning the following error:

Unrouteable address

Now, I’ve added the domain as web domain too so that I can use SMTP credentials to send emails from the site, however the inbox of the domain mail email is hosted on 3rd party services. I believe the error is due to the fact that Hestia is looking for this inbox locally. How can I set that the inbox is hosted externally?

Regards

Don’t add the domain to mail domains and it should work fine

Yes, that I know (and that’s how promptly set that back) but by doing so I won’t be able to send emails from the site using SMTP validation unless I ask the client to write their 3rd party password and settings into the site setting. In cPanel there’s an option for the mail routing to be local or external, doesn’t HestiaCP have such option somewhere?

Any other idea?

May I do an up here?

Does the following help?

Thank you @Deepak I’ll give it a look