Hi,
I’ve bought the license and activated it.but when I want to create a new article on wordpress in admin panel, I cannot use neither front end nor backend, I see both of them they are there but when I click to open them the page doesn’t load and gets stuck, what’s the solution?
You need to contact the author of Visual Composer directly, if you require any support. This here is just the community forum for all Envato marketplaces, and not a support forum for specific items. 
I did, I thought maybe someone already had the same issue
Thanks anyway 
Often it’s a hosting or PHP issue if you are using the latest version of the plugin