Try restoring defaults and/or rebooting the dongle on another computer with Windows 7/8 or Windows 10 non-1709.
Check that the information that corresponds from the Command Prompt (cmd) > ipconfig and your mobile broadband dashboard matches your entries. It may also help to make some investigations in 'Control Panel > Network and Sharing Centre > Change Adapter Settings
> Your connection > Properties > Internet Protocol Version 4 (TCP/IPv4) > Properties' and trying once again (make sure your IP addresses and DNS server address (I only entered in the Preferred DNS server address) are indeed correct).
So...
IP address = IPv4 address (in cmd)
Subnet mask = 255.255.255.0 (automatically entered)
Default Gateway = Default Gateway address (in cmd)
Preferred DNS server = as Default Gateway address (in cmd)
Alternative DNS server = leave blank
Maybe also try to "Validate settings upon exit". I can't remember if I did this or not.