Rebalance operation is getting failed during downgrade from 5.5.3 to 5.1.1

We were testing the upgrade from 5.1.1 to 5.5.3 through CLI and upgrade has been completed successfully but while doing downgrade from 5.5.3 to 5.1.1, rebalance operation is getting failed.

 [root@mysql02 VBox_GAs_5.2.2]# couchbase-cli rebalance -c couchbase://mysql02.localdomain -u Administrator -p oracle
Rebalancing
Bucket: 00/00 () 0 docs remaining
[ ] 0.0%
ERROR: Rebalance failed. See logs for detailed reason. You can try again.

Log file contents:-

 
Rebalance exited with reason {badmatch, {error, {no_quorum, [{required_quorum, [majority, {majority, {set,2,16,16,8,80,48,

, [],[],[],[],[],[],[],[],[],[],[],[],[], [], ['ns_1@mysql02.localdomain', 'ns_1@mysql01.localdomain'], []}}]}, {leases,['ns_1@mysql02.localdomain']}]}}}ns_orchestrator 000ns_1@mysql02.localdomain10:34:32 PM   Tue Jan 8, 2019
Starting rebalance, KeepNodes = ['ns_1@mysql01.localdomain', 'ns_1@mysql02.localdomain'], EjectNodes = [], Failed over and being ejected nodes = []; no delta recovery nodes ns_orchestrator 004ns_1@mysql02.localdomain10:34:17 PM   Tue Jan 8, 2019