seems your server is listening on IPV6 port [::1] whereas the web exception you've reported is referencing to the IPV4.
Try to put EnableIPv6Support=0 in the Settings.ini file
Remember to leave a blank line at the end
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 :
<add name=" .... "
<DbProviderFactories /> (If this line is present, REMOVE it as noted in Step 4)
4- Remove the additional "<DbProviderFactories />" line
5- Save the file.
Thanks Qlik support!