无法读取配置节'configsections'，因为它缺少节声明

Question

I want to host a Wcf service on an IIS 10.0 on Windows Server 2016.

My app pool is v2.0 Integrated and the Wcf service was built with 3.5. Below web.config gets

The configuration section 'configsections' cannot be read because it is missing a section declaration. 

Service runs fine with same config on a w8.1 - IIS6.2 and on older Windows Server versions . What could be missing?

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <configsections>
     <sectiongroup name="system.web.extensions" type="system.web.configuration.systemwebextensionssectiongroup, system.web.extensions, version=3.5.0.0, culture=neutral, publickeytoken=31bf3856ad364e35">
       <sectiongroup name="scripting" type="system.web.configuration.scriptingsectiongroup, system.web.extensions, version=3.5.0.0, culture=neutral, publickeytoken=31bf3856ad364e35">
       </sectiongroup>
    </sectiongroup>
</configsections>

Answer 1

You should do like this

 <?xml version="1.0" encoding="utf-8"?>
    <configuration>
      <configSections>
         <sectiongroup name="system.web.extensions" type="system.web.configuration.systemwebextensionssectiongroup, system.web.extensions, version=3.5.0.0, culture=neutral, publickeytoken=31bf3856ad364e35">
           <sectiongroup name="scripting" type="system.web.configuration.scriptingsectiongroup, system.web.extensions, version=3.5.0.0, culture=neutral, publickeytoken=31bf3856ad364e35">
           </sectiongroup>
        </sectiongroup>
    </configSections>

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