Redgate Monitor displays this error when you try to connect from a Web Server to a Base Monitor that is a different version.

To fix the problem, you will need to manually remove the Base Monitor with the incompatible version.

1. On the machine running the Web Server, go to %ProgramData%\Red Gate\Redgate Monitor\
2. Open BaseLoction.config and remove the entry for the Base Monitor mentioned in the error message.
3. Restart the Redgate Monitor website.