Based on the error you are facing I would suggest you to contact OSIsoft Technical Support as it could mean there is a serious problem with the PI Archive Subsystem and your PI Data Archive might not be collecting data.
I experienced this error today while troubleshooting a PI-server collective that was out of sync. In my case it turned out to be because the archive disk was full so that the archive shift could not occur. The disk had 6GB free space but needed 8GB for new archive. After I freed up more disk space so that archive shift could proceed the error message disappeared.
The similarity to your case was that our PI OPC UA connector was unable to create new tags on this server while this error was active. Once it was solved the error in the OPC UA connector were gone.