Changing the role of sync gateway user

it was our scenario:
we have had a number of users on sync gateway and they logged in to sync gateway without any problem.
after we changed the role of sync gateways user, SG’s users couldn’t login and they saw the following error. “Invalid login”.
After we changed the role to “Full Admin” new users can log in without any error, but old users still have the same problem.

Looks like a duplicate of question that you posted here. Please delete this one so its tracked in a single place