Error in Elasticsearch logs: index.engine indexname [0] failed to acquire searcher, source indices_ttl

The following exception is thrown every minute in the logs

Error in Elasticsearch logs: index.engine indexname [0] failed to acquire searcher, source indices_ttl
java.lang.illegalstateexception: can't locate the origin of the current request.

Help on resolving this error.

Can you show us the entire error from the log?

[2016-07-26 11:49:43,461][ERROR][index.engine ] [hostname] [myindex][0] failed to acquire searcher, source indices_ttl
java.lang.IllegalStateException: can't locate the origin of the current request
at org.elasticsearch.shield.authz.accesscontrol.ShieldIndexSearcherWrapper.wrap(ShieldIndexSearcherWrapper.java:124)
at org.elasticsearch.index.engine.IndexSearcherWrappingService.wrap(IndexSearcherWrappingService.java:80)
at org.elasticsearch.index.engine.Engine.acquireSearcher(Engine.java:303)
at org.elasticsearch.index.engine.Engine.acquireSearcher(Engine.java:287)
at org.elasticsearch.index.shard.IndexShard.acquireSearcher(IndexShard.java:849)
at org.elasticsearch.indices.ttl.IndicesTTLService.purgeShards(IndicesTTLService.java:200)
at org.elasticsearch.indices.ttl.IndicesTTLService.access$000(IndicesTTLService.java:67)
at org.elasticsearch.indices.ttl.IndicesTTLService$PurgerThread.run(IndicesTTLService.java:140)
[2016-07-26 11:49:43,462][WARN ][indices.ttl ] [hostname] failed to execute ttl purge
[myindex][[myindex][0]] EngineException[failed to acquire searcher, source indices_ttl]; nested: IllegalStateException[can't locate the origin of the current request];
at org.elasticsearch.index.engine.Engine.acquireSearcher(Engine.java:316)
at org.elasticsearch.index.engine.Engine.acquireSearcher(Engine.java:287)
at org.elasticsearch.index.shard.IndexShard.acquireSearcher(IndexShard.java:849)
at org.elasticsearch.indices.ttl.IndicesTTLService.purgeShards(IndicesTTLService.java:200)
at org.elasticsearch.indices.ttl.IndicesTTLService.access$000(IndicesTTLService.java:67)
at org.elasticsearch.indices.ttl.IndicesTTLService$PurgerThread.run(IndicesTTLService.java:140)
Caused by: java.lang.IllegalStateException: can't locate the origin of the current request
at org.elasticsearch.shield.authz.accesscontrol.ShieldIndexSearcherWrapper.wrap(ShieldIndexSearcherWrapper.java:124)
at org.elasticsearch.index.engine.IndexSearcherWrappingService.wrap(IndexSearcherWrappingService.java:80)
at org.elasticsearch.index.engine.Engine.acquireSearcher(Engine.java:303)
... 5 more
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