For correct work of application:
1) Open “Settings ⟶ Installed Apps ⟶ Prof Reminder”
1.1) Turn ON “Autostart”,
1.2) Turn ON “Permissions ⟶ Start in background”,
1.3) Select “Battery saver ⟶ No restriction”.
2) In “Security ⟶ Gear ⟶ Boost speed ⟶ Lock apps” turn ON Prof Reminder.
3) In “Settings ⟶ Battery & performance ⟶ Power settings” select “Performance”.