[themoonisachees]

Because Gmail treats + as an alias, they disable using + specifically so you don't use an alias, either creating multiple accounts or making them collect an easily blockable email ad target.

If you own a Google domain (not for long unfortunetaly, but I hear cloud flare has the same service) you can define *@domain for free and any email sent to the domain ends in the inbox of your choosing. Unlimited adresses.

[chrismorgan]

Catch-all is a pretty standard feature across email providers when you’re using your own domain.

As for +, I have no idea if it’s being blocked on purpose or by accident, but that kind of thing serves a useful purpose for the recipient, not just being able to create multiple accounts easily: automatic labelling. (And if you’re trying to create multiple accounts, plus addressing is an awfully prosaic approach, and there are plenty of other viable techniques, e.g. mail forwarding services, disposable addresses, adding random dots if you’re using Gmail—abc@, a.bc@, a.b.c@ and ab.c@ all go to the same mailbox.)