New Bad Gateway Error 502

Hallo Community,
I started an Cloudflare tunnel, with Docker and cloudflared in an Synology DS1812+ DSM 6.2.4. Update 6. The tunnel is established, but I cannot get to the gas from the outside, I receive this error message Bad Gateway 502, in the log file it reads: ” 2022-07-28T09:39:16Z ERR error=“Unable to reach the origin service x509: cannot validate certificate for because it doesn’t contain any IP SANs” cfRay=731ca58caa89bba1-FRA ingressRule=0 originService= https:"
any suggestions how I can get along?
I am looking forward hearing from you

Like it says, there is not a valid certificate on your service.

Either put a valid certificate on there or change it to not verify the certificate on the other end (not advised).

Dear Kian,

Thank you for your reply
I cecked the certificate installation, no failure.

I think it has to do with the nginx on my Synology 1812+
But I don’t know how to program the nginx server.

That certificate is not the one from your service. The service is the IP address you’re pointing to in your logs.

Hi Kian,

Thank you for your answer! Sorry - I am a bit puzzled. Do I get you right: I need a 3rd Certificate?
Were should it be installed?

where in this illustration?

The connection that needs a valid certificate is the one between Cloudflare and your “Ursprungsserver”.