Direct answer
A wrong result requires checking inputs, mode, calibration and output separately; a working control path can still be configured for the wrong state. For Android notification channels, first open the notification history/channel from a missed alert and send an in-app test.
What this covers
- Android notification channels with this exact failure state
- Diagnosis across app-wide permission versus one disabled channel, Focus and battery restriction
- Customer-accessible observation, settings and external components
What it does not cover
- ×A displayed manufacturer error code with a different documented meaning
- ×Live electrical, sealed-system, internal battery-cell or gas repair
- ×A claim that every model exposes identical controls
Capture the exact failure state
ReversibleWrite down the selected mode, input conditions and the exact unexpected output. Expected behavior: deliver each alert category with the selected sound, visibility and priority.
Isolate the component boundary
ReversibleOpen the notification history/channel from a missed alert and send an in-app test. Use a known reference input or manufacturer test and compare the result. Boundary to separate: app-wide permission versus one disabled channel, Focus and battery restriction.
Correct only the proven cause
ReversibleEnable only the needed channel and allow appropriate background activity. Correct the setting, calibration or component proven by that comparison.
Verify and stop safely
ReversibleRepeat with the reference and a normal real-world case. Preserve emergency and security alerts; do not disable all battery protection.
Evidence ledger
Sources behind this answer
Visible sources support the visible claims. Home Product Support records the publisher, the fact used and the review date; community reports can suggest an issue but do not become a published fact on their own.
Exact questions
Common follow-ups
What should I check first when Android notification channels has this problem?+
Open the notification history/channel from a missed alert and send an in-app test.
Why not factory-reset immediately?+
The useful boundary is app-wide permission versus one disabled channel, Focus and battery restriction. A reset can erase state without proving which side failed.
When should I stop troubleshooting?+
preserve emergency and security alerts; do not disable all battery protection.
Answer for the exact device and software version shown above.