Open PDF to add signature, and it just spins away, never opens signature

Hi this is too fold issue - First I am only familiar  with using Adobe for edit, adding signatures to contracts.  When the PDF comes in, I open it and click on edit/sign, but it just spins away. Never lets me add a signature.  So, I save the PDF, open it with Acrobat Reader DC and then is was  letting me sign.  NOW, Acrobat Reader DC won't let me add another signature, I click on the pen thing and it still only offers me existing signatures which I don't want.  Not sure what the problem is but I use this all day long and it's becoming a real issue!  HELP! Thanks