It may depends on some things. Can't he/she answer a few questions?
What browser does he/she use?
What kind of device does he/she use? (Exp. Computer/Ipad/mobile(if this one, what is the model of the mobile?/ etc...)

It might all depends, he/she may also changed some of his device/browser's setting which is causing this problem.
But, as a default help, i would say; (hopefully if he/she use a PC or laptop)
Log out, Reset the computer, Reset the browser's settings, Sign in MR, and see what will happen!

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But i really can't get it, he/she says:
whenever I try to anser somebody or to edit my post ...
So if he can't answer(Does he/she mean post?) what he/she is aiming to edit?
*Is he/she even got registered by Master Admin?