I route the traffic of my Webserver thought Cloudflare.
And the web features like https encryption work perfect.
But now I can’t connect to my server over the hostname with ssh.
How I can fix this problem?
You need to connect directly using the IP address.
Expanding from @sandro. CloudFlare only supports proxying certain ports listed here.
If you want to proxy other ports like 22 for ssh then it is available with Spectrum on the enterprise plan.