SSL Handshake failed with origin server, code: 525

I have configured full SSL on the free plan. The frontend side is working fine. But When I try to make a request to the backend side, it gives me the 525 handshake error like the below.

ake error.

And also this happens when I try to connect to the 8443 port with the domain name attached to it. Please help me with the issue.

A post was merged into an existing topic: Hello My site can’t connect to the backend