Bad gateway Error code 502 Cellmobile

I use Amazon aws to host an ecommerce site, and for some time now it has been giving me some 502 error messages. And now it has become more frequent. has anyone had this problem? I don’t have much knowledge of amazon aws so about settings, I don’t know how to do much on amazon. if anyone can give me any hint of what it could be, and if you want to test the site is cellmobile net, open some tabs and it already gives the error.