# No connection could be made because the target machine actively refused it

**URL:** <http://discussions.gridprotectionalliance.org/t/no-connection-could-be-made-because-the-target-machine-actively-refused-it/821>\
**Category:** PMU Connection Tester\
**Created:** [January 22, 2021, 5:17am UTC](http://discussions.gridprotectionalliance.org/t/no-connection-could-be-made-because-the-target-machine-actively-refused-it/821 "2021-01-22T05:17:43Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![aaronli-uga](http://discussions.gridprotectionalliance.org/user_avatar/discussions.gridprotectionalliance.org/aaronli-uga/32/688_2.png) [@aaronli-uga](http://discussions.gridprotectionalliance.org/u/aaronli-uga)\
**Post date:** [January 22, 2021, 5:17am UTC](http://discussions.gridprotectionalliance.org/t/no-connection-could-be-made-because-the-target-machine-actively-refused-it/821/1 "2021-01-22T05:17:43Z")

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I got a PSL microPMU device. After exploring the PMUConnectionTester, I ran into a problem that I tried for a while to solve but failed. Does anyone know how to solve it by any chance?

The error showed up when I clicked the connect button of the PMUConnectionTester. The attachment shows what the error said.

I am sure the IP address of the device and the device port are correct. I even tried disabling the firewall flag in the Security\_settings section of the setup.ini file.

My laptop has connected the PMU device via a network cable, and they are in the same LAN.

 ![WechatIMG2](http://discussions.gridprotectionalliance.org/uploads/default/original/1X/26b1aaa74d7761e1130709cea3da5a9c94034986.png)

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**Author:** ![ritchiecarroll](http://discussions.gridprotectionalliance.org/user_avatar/discussions.gridprotectionalliance.org/ritchiecarroll/32/2_2.png) [@ritchiecarroll](http://discussions.gridprotectionalliance.org/u/ritchiecarroll)\
**Post date:** [January 22, 2021, 6:07am UTC](http://discussions.gridprotectionalliance.org/t/no-connection-could-be-made-because-the-target-machine-actively-refused-it/821/2 "2021-01-22T06:07:44Z")

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You are trying to connect with TCP but the microPMU config settings say UDP, try switching to TCP.

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**Author:** ![aaronli-uga](http://discussions.gridprotectionalliance.org/user_avatar/discussions.gridprotectionalliance.org/aaronli-uga/32/688_2.png) [@aaronli-uga](http://discussions.gridprotectionalliance.org/u/aaronli-uga)\
**Post date:** [January 22, 2021, 3:48pm UTC](http://discussions.gridprotectionalliance.org/t/no-connection-could-be-made-because-the-target-machine-actively-refused-it/821/4 "2021-01-22T15:48:52Z")

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Thanks for your reply. Sorry for not showing the full name of that, which is **set communications protocol for PDC**. I am not sure if changing that would work. But I will try tomorrow.  
Thanks!

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**Author:** ![aaronli-uga](http://discussions.gridprotectionalliance.org/user_avatar/discussions.gridprotectionalliance.org/aaronli-uga/32/688_2.png) [@aaronli-uga](http://discussions.gridprotectionalliance.org/u/aaronli-uga)\
**Post date:** [January 22, 2021, 8:29pm UTC](http://discussions.gridprotectionalliance.org/t/no-connection-could-be-made-because-the-target-machine-actively-refused-it/821/5 "2021-01-22T20:29:42Z")

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**That was the problem**  
Thank you so much! It works now!