I haven't used a B & R PLC, but have used the OPC UA Client with many other servers.
Presumably you've been able to use the OPC UA Address Assist picker to locate tags so basic connection and tag browsing is working, so it's not likely that the x.509 certs are the issue.
Try drawing the driver instance Comms Stats button on a page to see what's being reported.
There's also the driver instance Diagnostics tab that has other info about the connection.
I haven't used a B & R PLC, but have used the OPC UA Client with many other servers.
Presumably you've been able to use the OPC UA Address Assist picker to locate tags so basic connection and tag browsing is working, so it's not likely that the x.509 certs are the issue.
Try drawing the driver instance [Comms Stats](https://www.vtscada.com/help/Content/D_Widgets/Dev_OPCUAClientStats.htm) button on a page to see what's being reported.
There's also the driver instance [Diagnostics](https://www.vtscada.com/help/Content/D_Tags/D_OPCUA_Tag.htm) tab that has other info about the connection.
Software Developer with Trihedral