Email messages sent from addresses outside of Zoho are not arriving starting about 9:30 am (eastern daylight savings time). I have tested sending email to myself from several different outside addresses. It hasn't bounced but it also hasn't arrived. Email from within Zoho seems to be arriving.
Update:
One of my test messages from 10:10 am just arrived now at 10:55 am. It is time stamped 10:10 am.
Update:
A message I received at 9:25 am just arrived again at 10:58 am. It's a duplicate of the exact same message with the exact same time stamp.
Update:
A test message I sent at 10:30 am just arrived now at 11:14 am with time stamp of 10:30 am. 45 minute delay.
Update:
A test message I sent at 10:53 am just arrived now at 11:52 am, so the lag is getting
worse, not better.