How can I reset the number of ADE authorizations I am allowed?

     Ever since I tried to add a second user to my Kobo Aura, I have not been able to open books downloaded from my local library.  I've tried many fixes, and some of them have resulted in my Kobo showing ADE as de-authorized.  Apparently I have exceeded the number of allowed authorizations, although all of them have been applied to a single device.