CWP7 – Let’s Encrypt SSL Renewal Gmail “Leaf Certificate” error

Recently, I ran into a bug with CentOS Web Panel. Several of my SSL certificates auto-renewed, and suddenly – Gmail was unable to send/receive email. Upon further inspection, Gmail reported “Leaf Certificate Error“.

After checking several certificate authorities, it appeared the SSL was indeed valid. There where no issue’s there. Yet, Gmail wasn’t willing to cooperate as I muddled about in it’s settings.

THE FIX: Restart a few services. On your CWP Dashboard, you can easily restart services. In my case, I restarted Apache, Varnish, Nginx, & BindDNS.

After that, a flood of email came in. One mail client was hung, as it seems Gmail gives up checking if it fails too many times. Via editing the account settings in Gmail, I was able to force it to try again via the “Check Mail Now” dialog – and all went through.

I’m not saying this is a bulletproof fix. But if you experience something similar, a simple restart of a few services could just do the trick.