Adobe News Aggregator

Please help! I have had persistent problems using the Adobe PDF Reader on my Mac. When I click on a PDF icon, a window appears telling me that I need to sign in. (See screenshot below.) It says, "Welcome Back," notes that I've previously signed in through Apple, and invites me to "Continue with Apple." I do not recognize the "Personal Account" name or the letters that appear in the bottom left-hand corner. Is this problem a sign of malware or a virus? I cannot get rid of this window, and it makes it impossible for me to do anything with the PDF--even to see it. I have been afraid to sign in at this window because I'm afraid that it is malware or a virus. To address this problem, I have deleted my Adobe and reinstalled it. This worked briefly a couple of times, but now the problem has returned and cannot be fixed by deleting and reinstalling. Does anyone have any suggestions for me? Thank you very much, in advance, for any help you can offer.