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) iManager => Security scan => « Wi-Fi Service » => Menu => Move to trustlist
2) Settings => Apps => App manager => « Wi-Fi Service » => Data usage => Background data & Unrestricted data usage => Turn ON
3) Settings => Apps => App manager => « Wi-Fi Service » => Battery usage => Background power control => Allow background power usage => Turn ON