# Opc client da/ua error establishing a connection: 11001

**URL:** <https://community.factoryio.com/t/opc-client-da-ua-error-establishing-a-connection-11001/1094>\
**Category:** Drivers\
**Created:** [October 12, 2021, 1:18am UTC](https://community.factoryio.com/t/opc-client-da-ua-error-establishing-a-connection-11001/1094 "2021-10-12T01:18:56Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![ricardorech](https://avatars.discourse-cdn.com/v4/letter/r/ee7513/32.png) [@ricardorech](https://community.factoryio.com/u/ricardorech)\
**Post date:** [October 12, 2021, 1:18am UTC](https://community.factoryio.com/t/opc-client-da-ua-error-establishing-a-connection-11001/1094/1 "2021-10-12T01:18:57Z")

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Hi all,

I’m new at Factory-IO and I’m facing a problem when trying to connect to an OPC-UA server, as described at the topic.  
It seems my OPC-UA server is working once I’ve read/write with other client simulator (UA Expert v1.5.1).  
I’ve done the basic stuff as desabling my firewall, restart computer, and so on.  
I’m using Factory-IO v2.5.0 and have a licence Modbus and OPC edition up to version 2.9.9.  
Does anyone here faced such a problem? Any help is very welcome.

![opc_ua_connectionError](https://europe1.discourse-cdn.com/flex017/uploads/factoryio/original/1X/e100b6bec5e5c02f2d74c19d95871a10d33af986.png)

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**Author:** ![brunovgr](https://dub1.discourse-cdn.com/flex017/user_avatar/community.factoryio.com/brunovgr/32/12_2.png) [@brunovgr](https://community.factoryio.com/u/brunovgr)\
**Post date:** [October 12, 2021, 3:39pm UTC](https://community.factoryio.com/t/opc-client-da-ua-error-establishing-a-connection-11001/1094/2 "2021-10-12T15:39:20Z")

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Can you share the URL of the OPC Server? It looks this is not a valid OPC UA server URL.

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**Author:** ![ricardorech](https://avatars.discourse-cdn.com/v4/letter/r/ee7513/32.png) [@ricardorech](https://community.factoryio.com/u/ricardorech)\
**Post date:** [October 12, 2021, 3:59pm UTC](https://community.factoryio.com/t/opc-client-da-ua-error-establishing-a-connection-11001/1094/3 "2021-10-12T15:59:08Z")

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Hi Bruno!

Thanks for your fast reply.  
find below a print of the OPC server I’m trying to connect. Just to make thinks a bit clear, I’m trying to communicate 4diac-FORTE ([Eclipse 4diac - The Open Source Environment for Distributed Industrial Automation and Control Systems](https://www.eclipse.org/4diac/)) which is the OPC-server with Factory-IO as a OPC client, both are running locally on my laptop.  
As soon as I select the server (DESKTOP-LE0BM9S-forte\_4840) I got the error.

 ![OPC_server](https://europe1.discourse-cdn.com/flex017/uploads/factoryio/original/1X/3a4577e6742da2e216b1df3ca179d1e01aa6a2d2.png)

B.R.  
Ricardo

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<div class="post-metadata">

**Author:** ![brunovgr](https://dub1.discourse-cdn.com/flex017/user_avatar/community.factoryio.com/brunovgr/32/12_2.png) [@brunovgr](https://community.factoryio.com/u/brunovgr)\
**Post date:** [October 18, 2021, 4:32pm UTC](https://community.factoryio.com/t/opc-client-da-ua-error-establishing-a-connection-11001/1094/4 "2021-10-18T16:32:21Z")

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Hi Ricardo,

I apologize for the late reply.

Please try to connect by typing directly the OPC server URL in the OPC server input field. The URL has the following format: opc.tcp://localhost:#### where #### is the OPC server port number. See the following image as an example:

![image](https://europe1.discourse-cdn.com/flex017/uploads/factoryio/original/1X/913d9d57b66392e98e0577cbd43a2c3493be23b8.png)

After typing the correct URL press Enter and see if it can connect.

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<div class="post-metadata">

**Author:** ![ricardorech](https://avatars.discourse-cdn.com/v4/letter/r/ee7513/32.png) [@ricardorech](https://community.factoryio.com/u/ricardorech)\
**Post date:** [October 30, 2021, 1:12am UTC](https://community.factoryio.com/t/opc-client-da-ua-error-establishing-a-connection-11001/1094/5 "2021-10-30T01:12:45Z")

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Hi Bruno!

Many thanks for your feedback.  
By trping the OPC URL directly it works properly.