Bit of a weird one this.
Emails sent to me @ the apple .me.com address are getting through to my phone, but ones sent to .icloud.com are not.
I can send OK, and I can receive gmail and an imap account’s mail fine.

So username@me.com gets to me, but username@icloud.com doesn’t, when previously it did.
I’m away in Portugal and relying on the 3G signal on my phone if that makes any difference?

Any ideas?

Try loggin out and back in to iCloud on the phone. I have found mail inc gmail can be a bit intermittant. Can yousee messages on other devices and/or via web browser