Survey Solutions uses C# language for writing the expressions, such as enabling or validation conditions. Yet, where we thought the language features may be misused to create vulnerabilities, we’ve restricted its use by disallowing certain C# data types, such as accessing files or network.

If you are getting a “Forbidden type” error (corresponding error codes are WB0272, WB0273, WB0274, WB0275) the expression you’ve written is probably following the correct syntax, but is not going to compile for the reason of security.