Forwarding mail from aliases that use the same domain name as the destination mail address.

[jkelion]

When trying to create a mail box @somedomain.name to receive mail from aliases that were previously generated using the same @somedomain.name (configured under Custom Domains and that were previously forwarded to a protonmail address), one gets an "Invalid email" warning. Is there a way to get a domain's mail address to receive mail from already created aliases that use that same domain name? (obviously, with Catch All - Auto create on the fly alias - deactivated).