I've just signed up for an account to give it a try.  I've got everything setup and can now send emails from my domain, and receive emails as well.  

However, I am not able to receive emails from one specific sender - whose IP address is not listed on any spam or blacklist, and has an spf record.  

I'm also not able to receive emails sent from the zoho account to a hotmail account - its not in the spam folder either.  

Is there any way to fix this?