Choose what went wrong
If your child needs you, go to them first. Then use the clock's model name, the light you expected and what you actually saw to choose a check. Do not reset the clock to its factory settings before reading what that reset wipes.
The light did not come on
Check that the clock is plugged in and switched on. Compare the time on the clock with the real time, including am and pm. Then check that the wake-up light is switched on: on some clocks the alarm sound has its own switch, separate from the light.
On MELLA, check that a sun or moon shows next to the time; if not, press SLEEP/WAKE. On Groclock, start the night or nap mode. On Mirari 8091, check the wake-light indicator separately from the alarm bell.
Use the preview or test in your clock's manual, if it has one. If the light still does not come on after those checks, tell the maker's support the model, the mode you switched on and what happened. Stop using a clock with a damaged cord or case and follow the maker's instructions.
The light came on at the wrong time or day
Compare the current time, the wake-up time and the days it is set for. Check that you changed the light's wake-up time, not the alarm time. If the clock moved between homes or time zones, check the time on the clock again before changing the routine.
Hatch Rest+ 2nd gen and Nanit Sound + Light can run different routines on different days. Do not assume a clock with a second alarm or a nap timer has a weekend schedule. Check which kind of second schedule you have, then correct the setting using its own instructions.
The problem began after a power cut
A saved setting does not mean the light kept running. MELLA's coin battery keeps the settings, but the light goes off until the power is back. Groclock freezes its time during a power cut, so set the clock's time again afterwards.
After the power is back, check the time, the mode and the light or sound you chose. If you do not know what your clock does in a power cut, tell your child the light may be off and go back to your usual morning until you have checked. The power guide explains what a battery that keeps the light on changes. Do not unplug the clock to test it unless its manual says to.
The app, or another grown-up, cannot change it
Work out whether the problem is setup, a lost connection or another person's access. Use the right account and pick the right clock before changing anything. Seeing a camera in an app does not mean you can change every setting on the clock.
On Hatch Rest+ 2nd gen, saved routines keep playing when the internet is down, but you cannot change them until it is back.
For invitations, use the sharing guide. If the maker's invitation or reconnect steps fail, contact the maker. Do not share passwords or reset a clock just to add another adult.
The light works, but its meaning is unclear
Look from where your child lies. Can they see the change without moving the clock or reaching its cord? Check the brightness, that the light faces the right way, and that you are not looking at the time display instead of the wake-up light.
Show the light during the day and ask your child to show you what happens next. If it is unclear or upsetting, stop expecting them to wait for it and practice together. Use words, pointing or signs your child already understands. If you are worried about how your child understands or communicates, talk to their doctor.
The light works and early mornings go on
A clock that works does not mean your child will sleep later or wait for the light. Ask what happened that morning: did they need the bathroom, feel frightened or need you? Deal with that first, then go back to the explanation you agreed.
Compare notes with the other grown-ups. Are you all saying the same thing and responding the same way? Does the quiet choice still fit your child? Look again at when help comes first and at your first setting, rather than making the wait longer or buying another clock. If your child wakes long before the light, see the early waking guide.
Talk to your child's doctor about sleep worries that go on. Frequent snoring, breathing problems at night or unusual sleepiness in the day need a pediatrician's advice soon. Trouble breathing now, or another emergency, needs urgent medical help.
Leave a note for the next grown-up
Write down the clock's model, the light and time you expected, what actually happened and which check you made. Add any recent power cut, account change or routine change. It gives the next adult, or the maker's support, a place to start.
Once the setting is fixed, update your plan and what to do if the light does not come on. The plan is a note for people; the change still has to be made on the clock or in its app.