553 Relaying disallowed

Hi guys, i need your help! I can send e-mails with my @rambla.co email but when i try to receive one i get the following message:

Technical details of permanent failure:

Google tried to deliver your message, but it was rejected by the server for the recipient domain rambla.co by mx.zohomail.com. [74.201.154.201].

The error that the other server returned was:

Any ideas on how to solve this issue? I would very much appreciate your input!

Thanks!