Error: Server is temporarily unavailable. Mail from this account has not been retrieved since 14:20. View details

Error: Server is temporarily unavailable. Mail from this account has not been retrieved since 14:20. View details

I've setup Pop3 mail in Gmail with zoho mail. I edit the connection details and it works ok for a short while and then I get this error message again.

See view details below.

24 October 2016 at 14:45 Error: Server is temporarily unavailable.
Server returned error "Error in RETR command: Received an empty line"
24 October 2016 at 14:28 Error: Server is temporarily unavailable.
Server returned error "Error in RETR command: Received an empty line"
24 October 2016 at 14:20 200 emails retrieved.  2694 emails remaining.
24 October 2016 at 14:12 200 emails retrieved.  2893 emails remaining.
24 October 2016 at 14:05 199 emails retrieved.  3093 emails remaining.

I am using these settings:

Incoming Server Name: poppro.zoho.com
Port: 995
Require SSL: Yes  
Username : you@yourdomain.com