unable to server-add (400) Bad Request

When creating a large cluster in AWS using cli, occasionally the following error occurs when attempting to add a node (frequency is approximately 1% of time on 100+ cluster)

failed: [54.154.138.144] =>

{"changed": true, "cmd": "/opt/couchbase//bin/couchbase-cli server-add -c ip-10-0-45-255.eu-west-1.compute.internal:8091 --user=Administrator --password=XXXXXXX --server-add=ip-10-0-253-237.eu-west-1.compute.internal:8091 --server-add-username=Administrator --server-add-password=couchbase --services=data", "delta": "0:00:35.101549", "end": "2015-09-30 12:58:45.321877", "rc": 2, "start": "2015-09-30 12:58:10.220328", "warnings": []}

stdout: ERROR: unable to server-add ip-10-0-253-237.eu-west-1.compute.internal:8091 (400) Bad Request
["Prepare join failed. Timeout connecting to \"ip-10-0-253-237.eu-west-1.compute.internal\" on port 8091. This could be due to an incorrect host/port combination or a firewall in place between the servers."]

Note: previously the script successfully check to see 10-0-253-237 is listening on port 8091. In addition the script is able to successfully initialise node 10-0-253-237