Could you verify that you are using the exact same value for “username” and “bucket”. Previous versions of libcouchbase allowed you to connect to the cluster with a different username than the bucket you wanted to use (for instance connect with administrator to operate on bucket “foo”). This isn’t something we think is a good practice to use (its similar to log into your unix system as root to su to the user you want to use), so it was decided to deny that usage. Unfortunately the error code (and message) isn’t correctly being propagated back to the user in PHP (there is a patch that will be part of the next release of the PHP extension).
Cheers,
Trond