[Upgrade] Add bucket through UI hangs after upgrade

1. Install 4.6.3-4050 on a single node cluster with kv,n1ql and index services.
2. create an admin role as:
/opt/couchbase/bin/couchbase-cli admin-role-manage -c 172.23.106.210:8091 --set-users=bob --set-names=Bob --roles=bucket_admin[bucket0] -u Administrator -p password
3. create a bucket bucket0.
4. Do an offline upgrade to 5.0.0-3270 using rpm -Uvh.
5. Upgrade succeeds but I am not able to add a new bucket in the cluster.
6. Also I am not able to edit the settings of current bucket in the cluster.

Attaching screenshots and logs.