503 Service Unavailable

I followed this guide and it worked for a few hours I could access to the panel without the port but after that the website just gives me 503 error…

If I remove the Rewriterule the website works as default website but if I add the rewrite rule again it keeps giving me the 503 error…

I also get 503 error in another website, happened the same the website worked a few hours and after that just 503 is shown.