This looks like a very common problem noticed in your Forum. I am facing the same now. My domain, theteashop.co.in. Now I am a little concerned. Is this whole mail thing buggy cause I would be using this for business mails and seeing the number of issues, and failing at the first step, I am concerned.
If so many people report the same issue, why is it not attended to at the root cause level instead of resolving it one person at a time ?
Please let me know if zoho is stable enough to be used as a business mailing solution or not. Any major concerns ?