So I was typing a link to my fictional country forum and when i clicked the link, this happened (can someone explain this)
Server Error in '/' Application.
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:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:

[HttpException (0x80004005): A potentially dangerous Request.Path value was detected from the client (:).]
System.Web.HttpRequest.ValidateInputIfRequiredByConfig() +9934053
System.Web.PipelineStepManager.ValidateHelper(HttpContext context) +55
Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.8.3928.0
Can someone help so I can fix the link?
(Edit:happened in my galaxy s5)