Currently when you create an alias in proton pass using a custom domain in my instance, by default it creates a 5 random letter/number suffix for example: .g43fs@example.com and it either auto fills the service name at the front: spotify.g43fs@example.com or expects you to enter a prefix.

This makes it easy for services to identify that you are using an alias for custom domains, without having to dig into the DNS records of the domain, which is unlikely anyway.

You can disable the suffix (called prefix) in the settings "Random Prefix Generation" but this leaves you having to randomly generate the full email address on your own, it is tedious.

We should have an option to fully randomly generate an email address including size for example: yjnf92fgu89aaet4s@example.com and it should work in the auto fill menu that creates an alias for you.