diff --git a/javascript/src/iframe/viamapi-iframe.js b/javascript/src/iframe/viamapi-iframe.js
index 53e0e1ae83568b2c2b18acde8196260ccc4154ce..1df7b53b1e79009ecb58efda7ad7f7f4ca658f41 100644
--- a/javascript/src/iframe/viamapi-iframe.js
+++ b/javascript/src/iframe/viamapi-iframe.js
@@ -1120,13 +1120,15 @@ const connection = Penpal.connectToParent({
       }
 
       const signatures = validateDocumentResponse.data;
-      for (const signature of signatures) {
-        const certificateChain = signature.certificateChainPEM.map((certificatePEM) => {
-          const certificate = parseCertificate(certificatePEM);
-          const certificateData = new CertificateData(certificate);
-          return certificateData;
-        });
-        signature.certificateChain = certificateChain;
+      if (signatures) {
+        for (const signature of signatures) {
+          const certificateChain = signature.certificateChainPEM.map((certificatePEM) => {
+            const certificate = parseCertificate(certificatePEM);
+            const certificateData = new CertificateData(certificate);
+            return certificateData;
+          });
+          signature.certificateChain = certificateChain;
+        }
       }
 
       return validateDocumentResponse;