Tip: for best results, turn on Airplane Mode ✈ to avoid outside notifications during your yoga practice.
If you are having trouble, consider the following solutions:
Be sure Fitness Tracking is enabled, otherwise haptic notifications will not work. To enable, open the Watch App on iPhone and tap on Privacy.
Make sure you are running the latest versions of iOS, watchOS, and of course silo.
If your watch is loose on your wrist, it may accidentally lock, showing a blue lock on the watch face. When it's locked, notifications may not go through.
Haptics will not work if iPhone or watch is in "Do Not Disturb" mode (it will work in Airplane Mode).
Consider increasing haptic strength: from WATCH go to Settings > Sounds & Haptics > increase Haptic Strength. Or turn on "Prominent Haptics" for an extra tap.
If you are using Bluetooth headphones via WATCH during a session, it could suppress the haptics.
To force quit the app on WATCH: hold down the Dock button, when power-off menu appears, hold down the Crown button.
For a reliable fix: delete the silo from your WATCH, then delete your iPhone, then reinstall from the App Store here.
And if those don't work: delete SILO app, then restart and/or restore WATCH and iPhone.