Mail function has been a little quirky following the Terms of Service changes but should be working ok now, or at least it was twenty minutes ago lol!
Remember all outgoing mail() must now use a valid email address belonging to the domain that is sending from in the headers or it gets binned as spam before it leaves the X10 server, so you can only send mail as yourself.
NB: SMTP mail is not affected because it uses other mail servers by default.