Lucee Administrator error

On our live servers in both Lucee Server & Web Administrators we get an error when trying to update the Settings/Logging values. I have searched online for the error and not found anything quite the same but am new to using Lucee Administrator so it could well be something very simple, any help appreciated.

The error we get is:

Cannot load class through its string name,
because no definition for the class with the specified name
[,,] could be found caused by
not found by lucee.core [64];,,;)


It’s Lucee Version