Hi, Zoho.  Today I am receiving the following error for the first time: "Reason:554 5.1.8 Email Outgoing Blocked."  

I have 0.02gb of storage used in my free account and have only once in the last 1.5 years sent an attachment of 1mb.  I hope that this blockage is not impacting any incoming email.

Could you kindly unblock my account and help me understand how I can avoid this in the future?

Thank you very much,

MATT