# OPC Client DA/UA can't connect to server

**URL:** <https://community.factoryio.com/t/opc-client-da-ua-cant-connect-to-server/508>\
**Category:** Drivers\
**Created:** [October 22, 2020, 9:16am UTC](https://community.factoryio.com/t/opc-client-da-ua-cant-connect-to-server/508 "2020-10-22T09:16:43Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![mommeja](https://avatars.discourse-cdn.com/v4/letter/m/eb9ed0/32.png) [@mommeja](https://community.factoryio.com/u/mommeja)\
**Post date:** [October 22, 2020, 9:16am UTC](https://community.factoryio.com/t/opc-client-da-ua-cant-connect-to-server/508/1 "2020-10-22T09:16:43Z")

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Hello,  
OPC Client DA/UA driver doesn’t find my OPC-UA server, neither using the browse button nor when I set manually the OPC Server input field with the correct end point address.  
The OPC-UA Server is located on the same machine where Factory I/O is installed.  
I know this is the correct end point address because on the same machine I have also another OPC Client that has no problem to connect with this end point address.  
I am using the following end point address. Is there any problem with this syntax?  
`opc.tcp://IVA1:4334/UA/MyLittleServer`

 ![serverdidnot](https://europe1.discourse-cdn.com/flex017/uploads/factoryio/original/1X/590bc46df1b2ed8eb83ef63dc3a2072d9d262ecf.jpeg)

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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 23, 2020, 4:57pm UTC](https://community.factoryio.com/t/opc-client-da-ua-cant-connect-to-server/508/2 "2020-10-23T16:57:16Z")

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Hi @mommeja,

Are you using the latest version of Factory I/O (2.4.3)? If so, I would say this issue is related to security settings on the OPC server. Can you tell me which server you are using? Thanks.

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<div class="post-metadata">

**Author:** ![mommeja](https://avatars.discourse-cdn.com/v4/letter/m/eb9ed0/32.png) [@mommeja](https://community.factoryio.com/u/mommeja)\
**Post date:** [October 23, 2020, 5:58pm UTC](https://community.factoryio.com/t/opc-client-da-ua-cant-connect-to-server/508/3 "2020-10-23T17:58:12Z")

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Bruno, thanks for your reply.

- Yes I am using 2.4.3
- I am using the node-opcua OPC server. More specifically the sample that was provided in this forum [https://community.factoryio.com/t/node-opcua-server/332/8](https://community.factoryio.com/t/node-opcua-server/332/8)  
In this sample, the server is instantiated this way, I guess there is no security at all. I don’t see what I should change, to allow the Factory I/O client to connect. Thanks for your guidance.  
const server = new opcua.OPCUAServer({  
port: 4334, // the port of the listening socket of the server  
resourcePath: “/UA/MyLittleServer”, // this path will be added to the endpoint resource name  
buildInfo : {  
productName: “MySampleServer1”,  
buildNumber: “7658”,  
buildDate: new Date(2014,5,2)  
}  
});

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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 26, 2020, 2:47pm UTC](https://community.factoryio.com/t/opc-client-da-ua-cant-connect-to-server/508/4 "2020-10-26T14:47:23Z")

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I’m facing exactly the same problem. I believe this issue is related to the latest versions of node-opcua (I have tested 2.22.0). By the way, all OPC clients I have tested with report the same error message. Most likely I’ll submit an issue on node-opcua.

Meanwhile, I have updated the sample server which is locked to version 2.7.0 and is working fine.