To do this, you can switch on the data roaming option on your device and check if your connection is working fine.
The steps for enabling data roaming may vary from device to device but they are typically located within the “network and Internet” settings. In Android, go to the Mobile network and finally search for the roaming tab.
Check Voxi Coverage
Coverage is another important for the link. If your smartphone does not receive sufficient coverage, the Internet connection can be very slow or may not be available directly.
You can test this by looking at the "bars" coverage in the status bar. But if you want to know the exact details you need to go to the settings and enter the system configurations.