Intermittent Failures in Email Forwarding

Intermittent Failures in Email Forwarding

I have set up forwarding on my Zoho email account to my personal gmail address.

When I first set it up everything seemed to work. (Well it had about a 5 minute delay before the emails would show up). However recently I started noticing that emails are no longer forwarding. A few days ago I noticed that some emails were not getting through, and now no emails are getting through.

What can I do to troubleshoot this? Any advice?

Jack