I just installed an Origin Certificate for SSL/TSL. It seems that since then Thunderbird can’t receive emails. I can send emails but I also get an error message "a copy was not placed in your sent folder due to network or file access errors. "
All was working fine before adding the Origin Certificate.
Are you using Cloudflare? Did you just add the origin certificate or do the whole Cloudflare setup?
Is the origin certificate the same for both the web and mail server? Are you using the Cloudflare origin certificate? (If so, that certificate is only designed for Cloudflare to connect to your origin, it won’t be trusted by other applications).
Cloudflare Origin certificates are only trusted by Cloudflare. That means they can only be used for HTTP(S) traffic proxied by Cloudflare, not for anything else (like email).
If you have problems with AutoSSL, you can create a Configuration Rule and disable Automatic HTTPS Rewrites and Browser Integrity Check, and also set Security Level to Essentially Off for the /.well-known/acme-challenge/ path.
If you have any WAF rules, you might also need to add an exception for this path.
You’ll want to use AutoSSL now to obtain a valid certificate.
Before that, create a Configuration Rule in Cloudflare to disable Automatic HTTPS redirect, Browser Integrity Check and set Security Level to essentially off for paths that start with: /.well-known/acme-challenge/