A potentially dangerous Request.Path value was detected from the client (?): Exception Details and Stack Trace

A potentially dangerous Request.Path value was detected from the client (?).

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Web.HttpException: A potentially dangerous Request.Path value was detected from the client (?).

Source Error:

Stack Trace:

[HttpException (0x80004005): A potentially dangerous Request.Path value was detected from the client (?).]
   System.Web.HttpRequest.ValidateInputIfRequiredByConfig() +678
   System.Web.PipelineStepManager.ValidateHelper(HttpContext context) +52

Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.8.4494.0