same issue for me…
I did an upgrade from 15.0 (working) to 15.1 and now I can not use kio-gdrive features directly in dolphin :{
The message is always the same “access grant not present”.
I have another 15.1 computer here and the service is working ok but I remember have had to delete all accounts and add them after upgrade.
Adriaan de Groot ([ade]) has updated his blog entry pointing to the Reddit entry – I missed the update – Thanks!
<https://euroquis.nl//kde/2020/05/12/google.html>
[HR][/HR]This happened during the openSUSE Forums migration to the new authentication system but, the fact that, the news that, KDE KMail is now “accepted” by Google was available during all phases of the migration …