IPhone has no alarm clock. Why does it keep ringing?

May be a health reminder; You can refer to the following methods:

1, first open the phone and click Health;

2. Go to Apple's mobile phone health page and click Sleep in your personal collection;

3. Enter the health status page and slide the phone screen upward;

4. Find and click all the timings and options at the bottom of the health page;

5. Enter all the timing and options pages;

6. On the timer page, turn off the switch behind the sleep timer, so that it won't ring without setting an alarm clock in the future.