Element 'ScriptManager' is not a known element. This can occur if there is a compilation error in the Web site.
Element 'UpdatePanel' is not a known element. This can occur if there is a compilation error in the Web site.
tried many things
checked web config file
reinstalled ajaxtoolkit
but nothing is working
getting error in the whole project
along with this getting error for other asp,net controls also
Element 'TextBox' is not a known element. This can occur if there is a compilation error in the Web site.