I'm using now LetsEncrypt SSL on my Ubuntu Server with Wordpress and Cloudflare (Apache+MariaDB).
Before installing SSL the server was running great, but now every day at 9pm the site goes down until 11pm and I don't know why, I start to think it's SSL. Although, when that happens, I can enter the site by IP, but not by domain..
If someone can help me with this I will aprecciate it a lot. I cannot find anything on logs of Apache...
To me, it sounds like a connectivity issue between your browser and the Cloudflare network. When you ping your domain, you're pinging Cloudflare's anycast servers, rather than your actual OVH server.
However, if this is happening to people from other households as well ... that really puzzles me.