Cannot send from iCloud to comcast

Hi  - as of yesterday, I cannot send from emClient to anyone with a comcast.net email address. I get the following message:

Your message cannot be delivered to the following recipients:  
  Recipient address:xxxxxxxx@comcast.net
  Reason: Rejection greeting returned by server.
  Diagnostic code: smtp;554 resimta-ch2-20v.sys.comcast.net comcast 17.172.80.95 Comcast requires that all mail servers must have a PTR record with a valid Reverse DNS entry. Currently your mail server does not fill that requirement. For more information, refer to: http://po
  Remote system: dns;mx2.comcast.net (TCP|17.172.80.95|59768|68.87.20.5|25)

I can send to comcast via my iPhone without any problem. Does anyone know what in the world changed?

Hello Andrew, I believe this is more likely a server issue, can you please navigate to Tools > Settings > Advanced and enable IMAP logging for the problematic account,

  1. Save the settings
  2. Restart the application
  3. Replicate the issue

Once the error reoccurs, please go back to the advanced settings window and submit the logging data to us for more information about the issue.
Please submit the data to my email mcgregor@emclient.com with a reference link to this forum topic.

Thank you.