diff --git a/src/main/java/com/sparrowwallet/sparrow/control/BlockCube.java b/src/main/java/com/sparrowwallet/sparrow/control/BlockCube.java
index d02e449c..b8722270 100644
--- a/src/main/java/com/sparrowwallet/sparrow/control/BlockCube.java
+++ b/src/main/java/com/sparrowwallet/sparrow/control/BlockCube.java
@@ -52,7 +52,10 @@ public class BlockCube extends Group {
     public BlockCube(Integer weight, Double medianFee, Integer height, Integer txCount, Long timestamp, boolean confirmed) {
         getStyleClass().addAll("block-" + Network.getCanonical().getName(), "block-cube");
         this.confirmedProperty.set(confirmed);
-        this.feeRatesSource.set(Config.get().getFeeRatesSource());
+
+        FeeRatesSource feeRatesSource = Config.get().getFeeRatesSource();
+        feeRatesSource = (feeRatesSource == null ? FeeRatesSource.MEMPOOL_SPACE : feeRatesSource);
+        this.feeRatesSource.set(feeRatesSource);
 
         this.weightProperty.addListener((_, _, _) -> {
             if(front != null) {
@@ -198,6 +201,8 @@ public class BlockCube extends Group {
                 } else {
                     feeRateIcon.getChildren().clear();
                 }
+            } else {
+                feeRateIcon.getChildren().clear();
             }
         }
     }
diff --git a/src/main/java/com/sparrowwallet/sparrow/control/RecentBlocksView.java b/src/main/java/com/sparrowwallet/sparrow/control/RecentBlocksView.java
index db47bd84..653c2e46 100644
--- a/src/main/java/com/sparrowwallet/sparrow/control/RecentBlocksView.java
+++ b/src/main/java/com/sparrowwallet/sparrow/control/RecentBlocksView.java
@@ -50,7 +50,9 @@ public class RecentBlocksView extends Pane {
             }
         }));
 
-        updateFeeRatesSource(Config.get().getFeeRatesSource());
+        FeeRatesSource feeRatesSource = Config.get().getFeeRatesSource();
+        feeRatesSource = (feeRatesSource == null ? FeeRatesSource.MEMPOOL_SPACE : feeRatesSource);
+        updateFeeRatesSource(feeRatesSource);
         Tooltip.install(this, tooltip);
     }
 
@@ -140,8 +142,10 @@ public class RecentBlocksView extends Pane {
 
     public void updateFeeRate(Map<Integer, Double> targetBlockFeeRates) {
         int defaultTarget = TARGET_BLOCKS_RANGE.get((TARGET_BLOCKS_RANGE.size() / 2) - 1);
-        Double defaultRate = targetBlockFeeRates.get(defaultTarget);
-        updateFeeRate(defaultRate);
+        if(targetBlockFeeRates.get(defaultTarget) != null) {
+            Double defaultRate = targetBlockFeeRates.get(defaultTarget);
+            updateFeeRate(defaultRate);
+        }
     }
 
     public void updateFeeRate(Double currentFeeRate) {