Guild Wars 2

It is what it says on the tin.
Specifically though, I cannot receive mail from players, but they can receive mail from me. I also can’t receive mail from the Black Lion Trading company store either.

There is a limit to the number of mails you can store. It’s supposed to be a max of 10 – but I think some people have run into issues if they’ve had 9 mails stored.

If this is what is affecting you, try deleting old mails that you don’t need anymore – the new ones should then start being delivered.