Getting signed out when trying to make a purchase

Hi, I keep getting signed out every time I try to make a purchase of the items in my cart. I don’t know how to fix this problem. Has anyone else had this problem? Does anybody have a solution?

I suggest you can contact to envato team. you can attach screenshots or screen recordings that will help easy understand the issue. i think this issue in only your side any browers issues, browser extentions you can check any PC or new browser.