This can be related to battery saving (some systems or some battery*saving applications disable third*party widgets background tasks). Try to check the settings (for example, in Xiaomi phones, this is called “Security> Autostart”, in Samsung “Maintenance> Battery”)
Supported Android
{4.0.3 and UP}
Supported Android Version:-
Jelly Bean(4.1–4.3.1)- KitKat (4.4–4.4.4)- Lollipop (5.0–5.0.2) – Marshmallow (6.0 – 6.0.1) – Nougat (7.0 – 7.1.1) – Oreo (8.0-8.1)