diff --git a/app/frontend/src/javascript/components/payment/payzen/payzen-keys-form.tsx b/app/frontend/src/javascript/components/payment/payzen/payzen-keys-form.tsx
index 82a1a3c74..a564bba56 100644
--- a/app/frontend/src/javascript/components/payment/payzen/payzen-keys-form.tsx
+++ b/app/frontend/src/javascript/components/payment/payzen/payzen-keys-form.tsx
@@ -71,6 +71,8 @@ const PayZenKeysFormComponent: React.FC<PayZenKeysFormProps> = ({ onValidKeys })
    * Depending on the test result, assign an add-on icon and a style to notify the user.
    */
   const testPublicKey = (key: string) => {
+    if (!key) return;
+
     if (!key.match(/^[0-9]+:/)) {
       setPublicKeyAddOn(<i className="fa fa-times" />);
       setPublicKeyAddOnClassName('key-invalid');