Android System Power Management
Starting with Android 5.0, many devices will act aggressively to try and
save system battery power. Unless certain steps are taken, Tasker may
not function as expected, either because Android is not sending it the
needed signals in order to save power or because Android is even killing
A commonly noticed symptom is that profiles with Time contexts don't activate
or deactivate at the expected time.
Tasker Run In Foreground Preference
Make sure that
Menu / Prefs / Monitor / General / Run In Foreground is checked.
Tasker Reliable Alarms Preference (Android 5.0+)
Menu / Prefs / Monitor / General / Use Reliable Alarms, make sure When Off or Always is selected.
If Never is selected, Android may group alarms together so they
go off too late. On some devices, Android may even kill Tasker at
times if Never is selected.
Android Battery Optimization Setting
If you have reliability problems, Tasker might need to be whitelisted
so that it is not battery-optimized by Android.
Vanilla Android Devices (Android 6.0+)
The location of the setting may vary per device, but a common method is to
launch the Android Settings app, select Apps, click the cog icon top-right,
then Battery optimization. Click All apps, then Tasker, then Don't optimize.
On a rooted device, it may be possible to change the battery optimiation
parameters depending on the functionality you need from Tasker. An example
app for this purpose is Naptime.
Samsung (Android 5.1.1+)
Some Samsung devices have a Smart Manager app. Launch the app,
press the battery quarter of the screen, under App optimisation press
DETAIL where you can adjust the settings for each app. It's advisable
to disable this for Tasker if you are having reliablity problems.
Launch Settings app, select Additional settings -> Battery & performance -> Manage apps battery usage -> OFF