KEPServerEX with OPC UA Client driver cannot write to tags on Wonderware server.
Hello, I have and old Kepware installation that uses OPC DA to communicate with tags in Wonderware. I am trying to update from OPC DA to OPC UA. All was looking good; I was able to install the OPC UA Client driver, configure it, connect to the Wonderware server, and read all tags with good quality.
The problem is that I cannot write to the tags. The tags are configured to be read/write in both Kepware and Wonderware. However, when I try to use the OPC Quick Client to write to any tag the following entry appears in the KEPServerEx log: OPC UA Client Async Write failed for 'ns=3;s=1510:IMIS.TAG1.Value' on device 'WWChannel.Wonderware'. Callback item error: 0x80004005.
I have tried turning off the firewall but had the same results. From what I could read about 0x80004005 there is some resource that cannot be accessed but it is unclear which resource. Does anyone have experience with this error or have any suggestions on what to try to resolve it?
Thank you for looking at this post.

