A message is waiting inside an app, yet the iPhone never announced it. If this happens around the same time each evening, check Focus before treating it as a delivery problem. The useful question is not simply “did the phone make a sound?” but “which rule was active when the message arrived?”
Identify the active rule
Open Settings, Focus, and the mode involved. Look at its schedule: a Focus can start by time, location or app. For Sleep Focus, also check the sleep schedule in Health. Make a note of the condition you actually find instead of assuming every evening activation follows a clock.
Consider a schedule starting at 21:00. A message at 20:55 and one at 21:05 are not necessarily being handled under the same conditions. First confirm that both reached the app, then note whether Focus was active at each time. This separates arrival from the way the phone presents an alert.
Read the list’s purpose before editing it
People and app lists can allow notifications or silence them. A name appearing in a list is therefore not enough to tell you what will happen; read the option selected above it.
Keep the quiet period if it is useful, and adjust one relevant exception rather than deleting the whole schedule. Ask someone willing to help to send a nonurgent test message, or wait for the next ordinary notification. An allowed notification still does not prove that every other sound and app setting is correct.
Finally, check the next scheduled activation. A manual change that solves tonight’s interruption may leave tomorrow’s automatic behavior untouched. Keep a short note of the schedule, list type and change so you can undo precisely what you adjusted.