# What does the error "Existing open connection detected" mean?

**URL:** <https://community.neo4j.com/t/what-does-the-error-existing-open-connection-detected-mean/64063>\
**Category:** Newbie Questions\
**Created:** [September 8, 2023, 7:44am UTC](https://community.neo4j.com/t/what-does-the-error-existing-open-connection-detected-mean/64063 "2023-09-08T07:44:50Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![brieuc.kaisin](https://sea1.discourse-cdn.com/flex021/user_avatar/community.neo4j.com/brieuc.kaisin/32/29614_2.png) [@brieuc.kaisin](https://community.neo4j.com/u/brieuc.kaisin)\
**Post date:** [September 8, 2023, 7:44am UTC](https://community.neo4j.com/t/what-does-the-error-existing-open-connection-detected-mean/64063/1 "2023-09-08T07:44:51Z")

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Hello. During a query to my Neo4j database, I encountered the following error:  
java.util.concurrent.CompletionException: java.lang.IllegalStateException: Existing open connection detected

Does someone know what caused this error, and how to solve it ? Thanks a lot!

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<div class="post-metadata">

**Author:** ![jennifer\_reif](https://sea1.discourse-cdn.com/flex021/user_avatar/community.neo4j.com/jennifer_reif/32/8061_2.png) [@jennifer\_reif](https://community.neo4j.com/u/jennifer_reif)\
**Post date:** [December 5, 2023, 9:58pm UTC](https://community.neo4j.com/t/what-does-the-error-existing-open-connection-detected-mean/64063/2 "2023-12-05T21:58:03Z")

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On what type of instance are you running this query (Neo4j Aura, cloud provider, Neo4j Desktop, somewhere else)? Sounds like there may be an existing query hanging up the connection.