If the Android apps on your Sailfish device are able to reach the Internet over WLAN but not over mobile data, check the protocol used:
- Open Settings > Mobile network > Data access point
- Tap Protocol
- If you have "Dual" or "IPv6" chosen, take "IP" (this means IPv4)
- Close Settings
- Restart the device.
NOTE: On dual SIM devices there are two menu items with the name "Data access point", one for for each SIM card.
Try the Android apps now.