400 Bad Request - No access to cpanel after switching to cloudflare

I recently switched to Cloudflare Nameservers from namesilo/hostsilo Nameservers. I didn’t change any records or anything else really, I merely switched out the Nameservers.

Now after doing so I cannot access my cpanel with the key :2083 anymore.

The error says word for word:
400 Bad Request
The plain HTTP request was sent to HTTPS port

Does Anybody know how to fix this so I can get cpanel access again?



Can you try the solutions provided in this previous community post with the same issue?