Global.asax wurde gefixed-

Web.config

@@ -29,6 +29,7 @@
     </authentication>
     <sessionState mode="InProc" timeout="2880" cookieless="true" regenerateExpiredSessionId="true" compressionEnabled="true" />
     <httpRuntime requestValidationMode="2.0" targetFramework="4.7" />
+	  
     <pages validateRequest="false" controlRenderingCompatibilityVersion="4.0" />
     <!--<securityPolicy>
       <trustLevel name="Full" policyFile="internal"/>
@@ -120,6 +121,8 @@
   </runtime>
 	<appSettings>
 		<add key="ValidationSettings:UnobtrusiveValidationMode" value="None" />
+		<add key="ClientValidationEnabled" value="true"/>
+		<add key="UnobtrusiveJavaScriptEnabled" value="true"/>
 	</appSettings>
 </configuration>
 <!--ProjectGuid: 9b651bc0-361a-4f93-8118-dd8a986f2371-->