When I BCC myself sending email, i get rejected by the server. If I remove my BCC it then rejects the recipient.

When I BCC myself in emails I get an error message that says my address is rejected by the server and its placed in the outbox. If I add a CC it will reject the CC and still not send the email. If I delete both, it wont send it again as it rejects the recipient. I am using an iPad Air. My husbands iPad 2 does not have the issue, we both use the same server and we both have the same settings. Only started happening last week.