No email availability

My email had been working but now

When I go to my email I am now getting just a white screen with the words::

No message Selected

and yet there are emails being sent because I see the number of emails increasing beside my email icon. But When I click that icon all I see is a white screen with the words

No Message Selected

there is no availability to close (by hitting the “done” button top right) there is only 3 icons at the bottom of that white page (trash can, folder, back arrow) none of those when touched work.

Please tell me what I need to do,