Hello mggytis,

maybe it is the topic, which is described in the following FAQ:
"Why can you no longer connect the WinCC OPC Client to OPC servers after
upgrading to WinCC V7.3 and higher or to WinCC Professional V13 SP1 and higher?"

https://support.industry.siemens.com/cs/ww/en/view/109483815

Regards

Georg Berghof

Hello mggytis,

this case needs a more detailed investigaton, therefore you should use the
SIMATIC Assessment Suite - Data Collector (SAS-DC) - formerly known as SIMATIC
Diagnostics Tool (SDT) - to collect diagnostics and system information from
the Computers.

https://support.industry.siemens.com/cs/ww/en/view/65976201

Then create a Servicerequest, and send the data to the
Technical Support of SIEMENS.

Regards

Georg Berghof