Eyedropper tool for fill not working

That's very strange. Things that could be the cause - and since it's a web-based app, may have to do with the browser. Namely cookies (try to clean them) and maybe try another browser (accepted browsers for now are Chrome, Safari and Edge)
Particularly, if you have things like ad-blockers and pop-up blockers, you need to disable them (You might just disable them for Adobe Express and not the rest of the websites you use)
Lots of features get deactivated if you have some blocking involved.

No specific error message - when I click on the eyedropper tool it just does not register the click. I've recently just had to color match by choosing a similar color to the best of my ability which has been very frusterating :,( 

Do you have a specific error message?
I just tested it, and it worked fine for me (picking the skin colour to change the text colour)