I suspect a problem with authentication, as that was one of the big changes from 4.x to 5.x. Was this a rebalance upgrade? If so, can you confirm that the 5.x cluster has a user created which has the same name as the bucket?
I suspect a problem with authentication, as that was one of the big changes from 4.x to 5.x. Was this a rebalance upgrade? If so, can you confirm that the 5.x cluster has a user created which has the same name as the bucket?