Just started having this problem.  Both the "email or phone" and "password" boxes are highlighted in red with my actual email and password imposed over the top of these terms.  The keep me logged in box is checked. 

It will not let me log in until I go into the boxes and delete and reenter at least one of the characters.  At that point the imposition goes away, the boxes are blue and all that is left is my email and password, which once I click on sign in, gets me into my email without further issue.