# Cannot start logstash after adding netflow module

**URL:** <https://discuss.elastic.co/t/cannot-start-logstash-after-adding-netflow-module/119133>\
**Category:** Logstash\
**Created:** [February 8, 2018, 10:21pm UTC](https://discuss.elastic.co/t/cannot-start-logstash-after-adding-netflow-module/119133 "2018-02-08T22:21:15Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![imortalsolitude](https://avatars.discourse-cdn.com/v4/letter/i/6f9a4e/32.png) [@imortalsolitude](https://discuss.elastic.co/u/imortalsolitude)\
**Post date:** [February 8, 2018, 10:21pm UTC](https://discuss.elastic.co/t/cannot-start-logstash-after-adding-netflow-module/119133/1 "2018-02-08T22:21:16Z")

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When i modify the logstash.yml to add netflow module my logstash never starts and gives below error" [logstash.agent] Failed to execute action {:action=\>LogStash::PipelineAction::Stop/pipeline\_id:main, :exception=\>"NoMethodError", :message=\>"undefined method `map' for nil:NilClass\nDid you mean? tap", :backtrace=>["/usr/share/logstash/logstash-core/lib/logstash/util.rb:40:in`thread\_info'", "/usr/share/logstash/logstash-core/lib/logstash/pipeline.rb:662:in `block in plugin\_threads\_info". i am using the instructions as specified [here](https://www.elastic.co/guide/en/logstash/6.2/netflow-module.html) except the port has been changed

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**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [March 8, 2018, 10:21pm UTC](https://discuss.elastic.co/t/cannot-start-logstash-after-adding-netflow-module/119133/2 "2018-03-08T22:21:16Z")

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