You can disable request verification by setting validaterequest = false in the page instruction or configuration section.

Note: The request verification process detects potentially dangerous client input values. The request processing has been suspended. This value may indicate that the application is compromised. ProgramSecurity attempts, such as cross-site scripting attacks. In
Set validaterequest to false in the page instruction or configuration section.
You can disable request verification. However, in this case, it is strongly recommended that the application explicitly check all input.

Solution:
Method 1. Add the following on the. ASPX page:
<% @ Page validaterequest = "false" %>
Method 2: Modify the Web. config file:
<Configuration>
<System. Web>
<Pages validaterequest = "false"/>
</System. Web>
</Configuration>