Memcached #32 error

while backing up bucket using cbbackup getting below error:
(u’error: SASL auth failed: 10.38.7.149:11210, Memcached error #32: {“error”:{“ref”:“0c23b987-ca24-4764-cd6d-39b8e08cd6c0”}}’, None)

Query Used:
cbbackup http://localhost:8091 /home/ec2-user/backup/test_bucket --username Administrator --password password -b test_bucket.

Couchbase version is 5.0.1
Previously this query was running fine.

Could you try to locate 0c23b987-ca24-4764-cd6d-39b8e08cd6c0 in server logs of memcached?