From your comment I understand that you are able to access your Fiori app on your laptop/desktop, the only issue is from the Fiori client. Hope my understanding is correct.
In this case I see that the mobile device is not able to reach the Fiori launchpad URL. Please verify if you can access your URL outside your corporate network. If not, please connect to your VPN and then try to configure it.
Hope it works. If not, please let us know.
Regards,
Nagesh