diff --git a/src/p4/ComplexMessage.svelte b/src/p4/ComplexMessage.svelte
index a17ffbb..9bd253b 100644
--- a/src/p4/ComplexMessage.svelte
+++ b/src/p4/ComplexMessage.svelte
@@ -17,7 +17,7 @@
       if (isText) {
         el.appendChild(document.createTextNode(part));
       } else {
-        const value = values[part];
+        const value = values && values[part];
         if (value) {
           const node = document.createElement('a');
           node.href = value.href;