Error: A Potentially Dangerous Request.Form Value Was Detected From the Client

An error occurs when saving a form that includes HTML tags. This is error is produced by a security layer to intended to prevent XSS attacks and will appear when submitting HTML tags in most form fields. There are a few fields that support HTML tags including the description fields for Courses, Events, Plans, and Resources. If your seeing this error when submitting a form that is intended to support HTML Tags, you may need to update the requestValidationMode in the web.config from 2.0 to 4.5.

Steps to Reproduce

1. Change the web.config: requestValidationMode="2.0".

2. Edit a Course and add <b>bold text</bold> to the description.

Resolution

Change the web.config: requestValidationMode="4.5".