Parser Error Message: Unknown server tag: Different behavior on different environments

Question

So we have two environments A: Win 2016 with IIS all features installed hosted in Amazon B: Win 2016 with IIS all features installed hosted in Azure

We have site over in Amazon which was built for framework 4.5 and works perfectly The same site when moved over to Azure throws Parser Error: Unknown server tag

<pages theme="Default" controlRenderingCompatibilityVersion="3.5" clientIDMode="AutoID">
        <controls>
            <add tagPrefix="eimac" namespace="EIM.Common.Utility.Repository.WebControls" assembly="EIM.Common.Utility.Business"/>
            <add tagPrefix="ajax" namespace="AjaxControlToolkit" assembly="AjaxControlToolkit"/>
            <add tagPrefix="eim" namespace="EIM.Common.Web.UI.WebControls" assembly="EIM.Common"/>
            <add tagPrefix="acme" namespace="EIM.Client.Acme.AcmePortal.Web.Controls"/>
        </controls>
    </pages>

Any suggestions what could be going wrong between two servers? We have compared installed features w.r.t .NET framework on both servers and they match. Both servers have .NET 3.5 and 4.6 installed and we manually registered the both .NET framework versions with IIS.