If the Reference Synchronizer isn't displaying anything — no error, just blank — it's almost always one setting: Publisher Trading Hours Name.

This property has to match the trading hours your Market Profile chart is actually using. Out of the box it defaults to CME US Index Futures RTH. If that's not the trading hours on your chart, the indicator has nothing to sync to and simply shows nothing.

To fix it:

1. Check your Market Profile chart's trading hours: right-click the chart → Data Series, and note the Trading hours value shown there.
2. Right-click the chart → Indicators, and select Reference Synchronizer.
3. Set Publisher Trading Hours Name to the same trading hours from step 1 — it has to mimic your Market Profile data series exactly.
4. Click OK / Apply.

Once the two match, it'll display correctly.