I'm using personal certificate sign for my emails and recently I discovered, that emails sended from my iOS Mail app over msync.zoho.com have problems with certificate.

I did little investigating over this and found, that this happend only over ActiveSync protocol. When I set up my account on iPhone again over IMAP, certificat is OK. But IMAP doesn't support PUSH on iOS so it's not usable for me.

Can you please look at this protocol, if there is some manipulating when message is sending that can casuse certificate damage?

Thank you.