Hello

For a few weeks now I have been having issues where I have an issue emailing some users. The error I am getting is Diagnostic-Code: Host not reachable, but I can email these users from my Gmail without issues. 

After speaking with Zoho on the phone, I have been told that it is an issue at the recipient end and that there is nothing they can do. I need to speak with the recipients' email provider.

On further investigation, I have found that CloudFlare is blocking Zoho mail and it seems that everyone I email who uses Cloudflare bounces back with the same "Host not reachable" error.

Advice would be a huge help.