UPDATE: Despite my search before posting, turns out this issue has been reported multiple times. The most active I found is here:
^^^ PLEASE go vote that issue up as well. ^^^
Unfortunately, the status on that issue is "NOT RIGHT NOW". This is probably because the company believes there is a work-around as posted by moderator @ChrisC. However, the temporary solution Chris suggests has been reported as not working by many people. I also confirm that deleting my password did not help.
Many users report that they put Spotify in Offline Mode, and sometime later when they start the app, it indicates they need to login. However, when they submit their login credentials, the app tells them they are in Offline Mode and must go online to login. This is a chicken & egg problem. This has nothing to do with Internet access--the failure happens even if connected to the Internet.
Users with a lot of downloaded content must re-download content upon re-install--making the uninstall/reinstall solution painful. For folks who are remote for multiple days, it means they have to go without Spotify until they have good Internet access again.
This may be an Andoid-specific issue.
The community is vocal about this issue:
@rly1music lists a lot of community threads about this same issue. This has been an issue for many months:
We have a post about this issue here. We suggest heading over for any updates about it.
Happy new year.