No Data Showing
Your surface or query shows no results. Here's how to diagnose and fix it.
Quick Diagnosis
Check these first:
- Is data flowing? Check connection status indicator
- Is surface connected? Verify surface is linked to correct connection
- Is time window correct? Expand the query time range
Step-by-Step Diagnosis
1. Check Connection Status
Go to your workspace and check the connection status:
| Status | Meaning | Action |
|---|---|---|
| Green | Data flowing | Connection is working |
| Yellow | Warning | Check connection configuration |
| Red | No data | Verify data source is sending |
| Gray | Unknown | Refresh or reconfigure |
If connection is red or gray:
- Verify your data source (IoT Hub, database, etc.) is running
- Check connection credentials
- Try the simulator to isolate the issue
2. Verify Surface Connection
Your surface must be connected to a data connection:
- Open your surface
- Check the connected data source
- Verify it matches the connection receiving data
Common issue: Surface connected to wrong connection or no connection.
3. Check Query Time Window
Your query might be looking at the wrong time range:
// Instead of this (last hour):
| where timestamp > ago(1h)
// Try this (last 24 hours):
| where timestamp > ago(24h)
Thinking Tip:
If data arrived before your time window, it won't appear in results. Start with a wider window, then narrow down.
4. Test with Simulator
Use the simulator to isolate whether the issue is your data source or your configuration:
- Connect a simulator to your surface
- Start the simulator
- If simulator data appears, the issue is your external data source
- If simulator data doesn't appear, check surface configuration
Common Causes
| Cause | Symptom | Solution |
|---|---|---|
| Data source not sending | Connection shows no data | Check external data source |
| Wrong connection | Surface shows other data | Reconnect to correct source |
| Query time window | Query runs but empty | Expand time range |
| Schema mismatch | Some fields empty | Check field names in query |
| Permissions | Access denied errors | Check team permissions |
Still No Data?
If you've checked all the above:
- Try creating a new test surface with the simulator
- Compare working vs non-working configurations
- Check the FAQ for edge cases