Actually, the problem was in Cloudflare, A2Hosting has added an "Add HTML" named app on Cloudflare to increase the website speed but they did some mistakes while creating the rules in that app, I have removed that app from Cloudflare, and the problem has been solved.
@slvrsteele please close this thread and thank you everyone for the help.
@slvrsteele please close this thread and thank you everyone for the help.
