Failed to execute operation for shard

I am shipping Windows events including auditing events to Elasticsearch using Winlogbeat. It was woking perfect but as soon as I configured two more file servers, their logs are not being reflected in Kibana. I can confirm through winlogbeat log that events are being shipped.

Here is the Elasticsearch log:

[2016-04-11 15:12:39,090][INFO ][node ] [TAMUQ-Elastic1] version[2.2.0], pid[14788], build[8ff36d1/2016-01-27T13:32:39Z]
[2016-04-11 15:12:39,090][INFO ][node ] [TAMUQ-Elastic1] initializing ...
[2016-04-11 15:12:39,606][INFO ][plugins ] [TAMUQ-Elastic1] modules [lang-expression, lang-groovy], plugins [], sites []
[2016-04-11 15:12:39,622][INFO ][env ] [TAMUQ-Elastic1] using [1] data paths, mounts [[D2 (e:)]], net usable_space [17.3tb], net total_space [17.4tb], spins? [unknown], types [NTFS]
[2016-04-11 15:12:39,622][INFO ][env ] [TAMUQ-Elastic1] heap size [15.1gb], compressed ordinary object pointers [true]
[2016-04-11 15:12:42,747][INFO ][node ] [TAMUQ-Elastic1] initialized
[2016-04-11 15:12:42,747][INFO ][node ] [TAMUQ-Elastic1] starting ...
[2016-04-11 15:12:43,060][INFO ][transport ] [TAMUQ-Elastic1] publish_address {}, bound_addresses {}
[2016-04-11 15:12:43,075][INFO ][discovery ] [TAMUQ-Elastic1] TAMUQ-Elasticsearch/yv9Ry8Z8RXGSN_tXFXK_xw
[2016-04-11 15:12:47,154][INFO ][cluster.service ] [TAMUQ-Elastic1] new_master {TAMUQ-Elastic1}{yv9Ry8Z8RXGSN_tXFXK_xw}{}{}, reason: zen-disco-join(elected_as_master, [0] joins received)
[2016-04-11 15:12:47,232][INFO ][http ] [TAMUQ-Elastic1] publish_address {}, bound_addresses {}
[2016-04-11 15:12:47,232][INFO ][node ] [TAMUQ-Elastic1] started
[2016-04-11 15:12:48,951][INFO ][gateway ] [TAMUQ-Elastic1] recovered [104] indices into cluster_state
[2016-04-11 15:13:16,359][INFO ][cluster.routing.allocation] [TAMUQ-Elastic1] Cluster health status changed from [RED] to [YELLOW] (reason: [shards started [[winlogbeat-2016.02.18][2], [.kibana][0]] ...]).
[2016-04-11 15:27:52,977][DEBUG][action.admin.indices.stats] [TAMUQ-Elastic1] [indices:monitor/stats] failed to execute operation for shard [[winlogbeat-fileaudit-2016.04.11][1], node[yv9Ry8Z8RXGSN_tXFXK_xw], [P], v[4], s[STARTED], a[id=cZ0p69B_R0O37lyJfR_l2A]]
ElasticsearchException[failed to refresh store stats]; nested: AccessDeniedException[E:\elasticsearch\data\TAMUQ-Elasticsearch\nodes\0\indices\winlogbeat-fileaudit-2016.04.11\1\index_8qk.fdx];

That looks like a permissions issue, I'd check the directory properties.

But it's working for other file servers.

Is there a possibility that Elasticsearch can't handle the quick influx of events? Is yes, how can I optimize Elasticsearch or run diagnostics?

Did you check the permissions or are you just asking random questions?

Yes, I did check and it's the same as before. What should I check in those permissions or are their any recommended permissions by Elasticsearch?