# OPC UA Client (Error 7001) - CODESYS v3.5 **URL:** \ **Category:** CODESYS\ **Tags:** codesys\ **Created:** [July 22, 2024, 6:39pm UTC](https://www.wago.community/t/opc-ua-client-error-7001-codesys-v3-5/1100 "2024-07-22T18:39:13Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![MikePsaltis](https://sea2.discourse-cdn.com/flex016/user_avatar/www.wago.community/mikepsaltis/32/47_2.png) [@MikePsaltis](https://www.wago.community/u/MikePsaltis)\ **Post date:** [July 22, 2024, 6:39pm UTC](https://www.wago.community/t/opc-ua-client-error-7001-codesys-v3-5/1100/1 "2024-07-22T18:39:13Z")
Hello Community, I am receiving an error with the OPC UA Client in CODESYS v3.5. There seems to be a limit for the number of connections. I can connect to 10 servers without any errors. When I connect to the 11th server, one of the connections drops and I receive this error. I did not see this error when I use the OPC UA Client in Node-RED, so I believe that this is a CODESYS limitation. ![image](https://us1.discourse-cdn.com/flex016/uploads/wago/original/1X/7519a62df34dc8b9ed9911c64b355b8c1e2ec115.png) I have the server and client for non-secured, anonymous connections. - Server (WBM Settings) PLC Runtime Port Authentication is also disabled (needed for Anonymous Connections) ![image](https://us1.discourse-cdn.com/flex016/uploads/wago/original/1X/8a0904a8e39d0b1134357155767093712f9f02b3.png) - Client (CODESYS Settings) ![image](https://us1.discourse-cdn.com/flex016/uploads/wago/original/1X/6fe02704f0ba29a8db2363eef4665f065bcd1a66.png) Thank you, ---
**Author:** ![MikePsaltis](https://sea2.discourse-cdn.com/flex016/user_avatar/www.wago.community/mikepsaltis/32/47_2.png) [@MikePsaltis](https://www.wago.community/u/MikePsaltis)\ **Post date:** [July 22, 2024, 6:41pm UTC](https://www.wago.community/t/opc-ua-client-error-7001-codesys-v3-5/1100/2 "2024-07-22T18:41:48Z")
I found a similar post on CODESYS Forge from 2022. It appears to be tied to TLSContext, but am still not able to make more than 10 connections with security set to “None”. [https://forge.codesys.com/forge/talk/Engineering/thread/aedd014bce/](https://forge.codesys.com/forge/talk/Engineering/thread/aedd014bce/) ---
**Author:** ![quenorha](https://sea2.discourse-cdn.com/flex016/user_avatar/www.wago.community/quenorha/32/429_2.png) [@quenorha](https://www.wago.community/u/quenorha)\ **Post date:** [July 23, 2024, 10:00am UTC](https://www.wago.community/t/opc-ua-client-error-7001-codesys-v3-5/1100/3 "2024-07-23T10:00:38Z")
I think you have to make an adjustment in the file /etc/codesys3.d/CODESYSControl.cfg [CmpOPCUAClient] MaxClients=20 Never tested though. ---
**Author:** ![MikePsaltis](https://sea2.discourse-cdn.com/flex016/user_avatar/www.wago.community/mikepsaltis/32/47_2.png) [@MikePsaltis](https://www.wago.community/u/MikePsaltis)\ **Post date:** [July 23, 2024, 2:10pm UTC](https://www.wago.community/t/opc-ua-client-error-7001-codesys-v3-5/1100/4 "2024-07-23T14:10:41Z")
Thank you, quenorha! I added this line to the .cfg file and it now allows more connections. In this case is set the MaxClients=16. I am currently testing the performance with the added connections. ![image](https://us1.discourse-cdn.com/flex016/uploads/wago/original/1X/e16dbd55e42de7bb1bdb02dffd91b9445b05ba89.png) ---
**Author:** ![TomasD](https://sea2.discourse-cdn.com/flex016/user_avatar/www.wago.community/tomasd/32/2042_2.png) [@TomasD](https://www.wago.community/u/TomasD)\ **Post date:** [July 3, 2025, 2:01pm UTC](https://www.wago.community/t/opc-ua-client-error-7001-codesys-v3-5/1100/5 "2025-07-03T14:01:23Z")
Good day, it seems that the file at this path does not exist. I have 8212, and here are the files I see in the directory: ~ ls -l /etc/codesys3.d/ -rw-r–r-- 1 root root 3189 Oct 23 2024 CmpWSServer.cfg -rw-rw-r-- 1 root root 431 Jul 3 16:30 CODESYSControl\_User.cfg -rw-r----- 1 root root 2389 Oct 23 2024 IoDrvDal.cfg -rw-r–r-- 1 root root 2220 Oct 23 2024 RtsCore.cfg -rw-r–r-- 1 root root 43 Oct 23 2024 TscSysProcessorLoad.cfg The desired file lies along this path. ~ ls -l /home/codesys\_root drwxrwsr-x 4 root admin 4096 Jan 23 18:45 cert -rw-rw-r-- 1 root admin 6184 Jul 2 16:34 CODESYSControl.cfg drwxrwsr-x 3 root admin 4096 Jan 23 18:45 OPCUAServer drwxrwsr-x 8 root admin 4096 Jul 1 11:25 PlcLogic The question is, in which file do you need to specify the maximum number?