Case solved by Qlik support.

This is a Microsoft .NET Framework issue.

The .NET Framework creates an extra " <DbProviderFactories />" line under the System.data.

Manually delete the extra line.

To modify the .Net Framework64 to address the issue, perform the following steps in order:

1- Browse to  "C:\Windows\Microsoft.NET\Framework64\v4.0.30319\Config

2- Using Notepad or similar editor, open "machine.config" (create a copy of this file prior to modifying)

3- Find the following section :

  <system.data>

    <DbProviderFactories>

      <add name=" .... "

   </DbProviderFactories>

<DbProviderFactories />  (If this line is present, REMOVE it as noted in Step 4)

  </system.data>

4- Remove the additional "<DbProviderFactories />" line

5- Save the file.

Thanks Qlik support!