These Settings must be properly configured to keep Mobile Tracker Free working.
Info: A password may be required to access the application settings. If you have not changed, the default password is *1234*. More information about the application password here.
1) Settings => Apps => See all X apps => « Wi-Fi » => Mobile data & Wi-Fi => Background data & Unrestricted data usage => Turn ON
2) Settings => Apps => See all X apps => « Wi-Fi » => Permissions => Location => Allow all the time