Hi Diego,
I see the 404 which means its not able to reach the Fiori Launch pad.
Few checks:
1. I also see Android VPN, please check if you are able to open the Fiori Launchpad with Android VPN without the fiori client.
2. Please confirm if you are able to Ping the Application configurations from SMP.
3. What is the authentication mechanism used, Basic / HTTP logins?
4. Is it a standard client or custom client?
If you need additional details on configurations, you can find some help at the following link:
Regards,
Nagesh