diff --git a/pkg/handlers/custom_metrics.go b/pkg/handlers/custom_metrics.go
index 4f658ae7a2..64ad490260 100644
--- a/pkg/handlers/custom_metrics.go
+++ b/pkg/handlers/custom_metrics.go
@@ -79,6 +79,10 @@ func validateCustomMetricsData(data ApplicationMetricsData) error {
 
 	for key, val := range data {
 		valType := reflect.TypeOf(val)
+		if valType == nil {
+			return errors.Errorf("%s value is nil, only scalar values are allowed", key)
+		}
+
 		switch valType.Kind() {
 		case reflect.Slice:
 			return errors.Errorf("%s value is an array, only scalar values are allowed", key)
diff --git a/pkg/handlers/custom_metrics_test.go b/pkg/handlers/custom_metrics_test.go
index 8e0b3bda1b..d588738764 100644
--- a/pkg/handlers/custom_metrics_test.go
+++ b/pkg/handlers/custom_metrics_test.go
@@ -53,6 +53,14 @@ func Test_validateCustomMetricsData(t *testing.T) {
 			},
 			wantErr: true,
 		},
+		{
+			name: "nil value",
+			data: ApplicationMetricsData{
+				"key1": nil,
+				"key2": 4,
+			},
+			wantErr: true,
+		},
 	}
 
 	for _, test := range tests {