Without exact system info and other details like version of PS nobody can even begin to tell you anything. Also start by checking whether your local Google Drive applet and your WebDAV connection are set up correctly and the permissions on the virtual drive and its folders are set correctly.
I didn't see an answer anywhere in that link 😕 Maybe it was deleted? Looks like a Google Community Specialist responded saying the issue has been reported, but there was no 'fix' in the thread. It's ~4 years later as of writing this post and this just happened to me. Looks like it's an ongoing issue.