diff --git a/service/src/main/java/lcsb/mapviewer/services/utils/ColorSchemaReader.java b/service/src/main/java/lcsb/mapviewer/services/utils/ColorSchemaReader.java
index eec055b8dd5dc73f0e90675dd5cc4fb925a7d784..2f358661b267053ed1a0db66055ad48d1d5e005c 100644
--- a/service/src/main/java/lcsb/mapviewer/services/utils/ColorSchemaReader.java
+++ b/service/src/main/java/lcsb/mapviewer/services/utils/ColorSchemaReader.java
@@ -569,7 +569,7 @@ public class ColorSchemaReader {
             errorPrefix + "Unknown class type: " + string + ". Valid values are: " + validStrings);
       }
     }
-    return null;
+    return result;
   }
 
   private Double parseValueColumn(String string, String errorPrefix) throws InvalidColorSchemaException {