This sounds like a general server setup issue rather than something specific to Codidact. You may also be able to get help elsewhere on general sysadmin help sites or groups. Either way, we'll need more information to be able to help you with this - what exactly is the error message? What are you doing? What do you expect it to do? What configuration are you using?

I try to launch rails db:create , I get connection errors I want to install webapp on Http://bimberspot.com not localhost !

Gate_sprit‭ Out of interest, how much sysadmin experience do you have? Setting this up on the public internet is certainly doable, but it does require some experience and ability to set up multiple components - you'll need DNS, preferably a reverse proxy like nginx or Apache, plus all the components of QPixel itself - Rails, MySQL, etc.