^^^ Surely that just counts as a statement of the bleedin' obvious doesn't it, Gingejbee? ;-)
(GMX is about a million billion trillion zillion squared times better than Yahoo and you can use the 'Mail Collector' function to get your Yahoo mail forwarded to it:
https://www.gmx.co.uk )
However your immediate problem is probably related to the way that your web browser handles the content from Yahoo. If 'switching it off and switching it on again' doesn't fix the problem, try resetting your web browser. (You'll need to tell us which one you're using if you require instructions).