Elasticsearch RED status in AWS

I have created an ES domain to search for the vpcglow logs and cloud trail log with daily indexing.
Right now, the status is RED :

"cluster_name": "678628912247:test",
"status": "red",
"timed_out": false,
"number_of_nodes": 17,
"number_of_data_nodes": 17,
"active_primary_shards": 687,
"active_shards": 1374,
"relocating_shards": 0,
"initializing_shards": 0,
"unassigned_shards": 8,
"number_of_pending_tasks": 0

Further investigating I found, one index is RED:

red open cwl-2016.02.19 5 1 381700 102899 335.8mb 167.9mb

Looking into the shards:

cwl-2016.02.19 2 p UNASSIGNED
cwl-2016.02.19 2 r UNASSIGNED
cwl-2016.02.19 0 p UNASSIGNED
cwl-2016.02.19 0 r UNASSIGNED
cwl-2016.02.19 3 p STARTED 381700 167.9mb x.x.x.x Elektra Natchios
cwl-2016.02.19 3 r STARTED 381700 167.9mb x.x.x.x Chronos
cwl-2016.02.19 1 p UNASSIGNED
cwl-2016.02.19 1 r UNASSIGNED
cwl-2016.02.19 4 p UNASSIGNED
cwl-2016.02.19 4 r UNASSIGNED

I tried to reroute the shards to less used nodes, but it gives me:

{"Message":"Your request: '/_cluster/reroute' is not allowed."}

Any advice please what I should do now.

Thanks & Regards.

Are you using the AWS ESaaS by chance?

Yes. I am. However, I got the status GREEN now. The took the backup of cluster and then deleted RED index.

The AWS service has a number of API limitations in place.