@joseph ~~Now I have reseted the router and I still have the same problem. I guess it's my ISPs Cgnat that is the problem. It's strange. It has been working for almost a year with the same ISP and the Cgnat but suddenly it stopped to work. I guess it's the Cgnat that make it impossible to ping the public ip too.
My apps with Cloudflare tunnels is working but the tunnel I created to the Cloudron dashboard gets bad gateway and host error from Cloudflare. What am I missing?~~
Now it's working. It was simple when I found it. I had forgot to activate No TLS Verify for the tunnel. Now it's working. Thank you for your help.
