Can't login to voicemail on mobile -only get PIN setup message

I have not changed anything on my phone since I last used Xfinity voicemail, about 2 days ago.  Now suddenly, when I try to login to my Xfinity voicemail from a *mobile* web browser, I can't get past an exasperating message that is asking me to setup a new PIN and security question.  I already have this PIN and security question created but the login doesn't seem to "know" it.  When I login from a desktop web browser, this does not happen.  That is, with a desktop browser, I can just login and go right to my voice mail without the message showing up.

That mobile browser PIN message is exasperating because it doesn't explain how to make the message go away!  It only says that I need to setup a PIN and of course that has already been done.

EDIT: Now the desktop browser is ALSO having the problem (displaying the message and preventing access to my VM).

Does anyone have an answer or work-around for this issue?

Thank You.