Hotmail has blacklisted Zoho
Got this since this morning:
This message was created automatically by mail delivery software.
A message that you sent could not be delivered to one or more of its recipients. This is a permanent error.
BLAHBLAHBLAH@hotmail.com, ERROR_CODE :550, ERROR_CODE :5.7.1 Unfortunately, messages from [31.186.226.248] weren't sent.
Please contact your Internet service provider since part of their network is on our block list (S3150). You can also refer your provider to
http://mail.live.com/mail/troubleshooting.aspx#errors. [AM5EUR03FT055.eop-EUR03.prod.protection.outlook.com]