Asp.net Validation not working for all project

Jun 3 2019 6:26 AM

Hi, i'm researching about for the days but unable to find a solution, suddenly my web application's validation stopped working, All was perfect some days ago, but now i checked a form its validation not working i go through the rest of application but all validation not working...

Can anybody guide me in this regard, why this happend have any dependency remove mistakely or something else?