Hello! I understand you're experiencing issues with alerts not sounding or vibrating on your Samsung S21 for PulsePoint Respond. Let's figure this out together!

First, let me ask a couple of questions to get more clarity:
- Are other apps providing sound or vibration alerts without any issues?
- Have you checked the notification settings for PulsePoint Respond specifically?

To start troubleshooting, here are a few steps you can take:

### Step 1: Check App Notification Settings
1. Go to Settings on your Samsung S21.
2. Tap on Notifications.
3. Find and select PulsePoint Respond from the list of apps.
4. Make sure that notifications are turned on.
5. Under the notification settings, ensure that both Sound and Vibration are enabled.

### Step 2: Check Volume Levels
Make sure your media and notification volumes are turned up:
1. Press the Volume Up button on the side of your phone.
2. Tap on the three vertical dots (more options) in the top right corner of the volume sliders.
3. Make sure Media volume and Ring volume are both set to a suitable level.

### Step 3: Reset App Preferences
If notifications are still not working, you may want to reset app preferences:
1. Go to Settings > Apps.
2. Tap on the three dots in the upper right corner and select Reset app preferences.
3. Confirm the action.

### Step 4: Notification Troubleshooting Tool in PulsePoint Respond
You can also use the notification troubleshooting tool within the PulsePoint Respond app:
1. Open the PulsePoint Respond app.
2. Look for the More Options icon (three dots or lines) typically found at the top right.
3. Select the troubleshooting option related to notifications, which can guide you further1.

Give these steps a try and see if the alerts start working again. Let me know how it goes! Are you satisfied with the solution I provided?