HSM cancel alerts doesn't stop siren?

[SmartHomePrimer]

The suggestion here was to uninstall and reinstall HSM, and that helped. Try it it might work for you to.

HSM canceling alerts

Did you try Disarm All? That will cancel alerts and return HSM to a disarmed state. Then you can re-arm water alerts. Also, if your water sensor is still reporting wet, HSM will alert again. That could have been your original problem. It is still armed after hitting cancel alerts, so if the device reports wet, around you go in a circle. Disarm All will allow you to check your water sensors, and get things back to a known dry state.