Webforms unobtrusivevalidationmode requires a scriptresourcemapping for ‘jquery’

In ASP.Net, in a specific situation, you may get this server error: webforms unobtrusivevalidationmode requires a scriptresourcemapping for ‘jquery’. Solution: Open web.config file. Below <appsettings> tag, add this key  <add value=”None” key=”ValidationSettings:UnobtrusiveValidationMode”/> See also The namespace Resources already contains a definition for PWA 2016. How to Encrypt Connection String in Web.config in ASP.NET