Several emails in Retry Queue

Several emails in Retry Queue

Hi,

The last couple of days, we have been experiencing issues with several emails being put in Queue or Retry Queue. Specially the ones being sent to Hotmail.com

Some of the error codes are:
ResponseCode 451, 4.7.500 Server busy.
ResponseCode 421, 4.7.0 Temporarily Deferred

Also, many people are saying that our emails have being going to their SPAM folder.

We have been very satisfied with Zoho in the past, but we are having a hard time now.
If these issues keep happening we must sadly consider to move to another provider.

Thanks.