Acrobat DC Already Signed In Under Another User

Hello.  I just started IT Support with my company.  I have a user who is trying to sign into Acrobat DC so she can sign and encrypt PDFs.  Her laptop is running Windows 10 Enterprise; her Acrobat Pro DC version is 2021.005.20060.  When we try to click on "Sign In," however, the cursor briefly changes to a wristwatch, but she doesn't get a prompt to sign in.  In fact, when I go to the "Help" menu, the drop-down shows a "Sign Out", and lists another user's account (our Network Engineer).  If I click on "Sign Out," I get the pop-up, "Sorry, something went wrong - Are you connected to the Internet?" The computer is, in fact, connected to the company Wi-Fi.  I have run through the Repair Tool, but it still doesn't allow to sign out.  I have tried uninstalling and reinstalling Acrobat DC more than once, but when I launch Acrobat DC, the other username is already signed in somehow.  How can we "reset" Acrobat DC on this computer so we can log the correct user in?  Thank you.