diff --git a/apps/viewer/layouts/ErrorPage.tsx b/apps/viewer/layouts/ErrorPage.tsx
index d734f4af4..595a6ea0e 100644
--- a/apps/viewer/layouts/ErrorPage.tsx
+++ b/apps/viewer/layouts/ErrorPage.tsx
@@ -11,8 +11,25 @@ export const ErrorPage = ({ error }: { error: Error }) => {
         flexDirection: 'column',
       }}
     >
-      <h1 style={{ fontWeight: 'bold', fontSize: '30px' }}>{error.name}</h1>
-      <h2>{error.message}</h2>
+      {!process.env.NEXT_PUBLIC_VIEWER_URL ? (
+        <>
+          <h1 style={{ fontWeight: 'bold', fontSize: '30px' }}>
+            NEXT_PUBLIC_VIEWER_URL is missing
+          </h1>
+          <h2>
+            Make sure to configure the viewer properly (
+            <a href="https://docs.typebot.io/self-hosting/configuration#viewer">
+              https://docs.typebot.io/self-hosting/configuration#viewer
+            </a>
+            )
+          </h2>
+        </>
+      ) : (
+        <>
+          <h1 style={{ fontWeight: 'bold', fontSize: '30px' }}>{error.name}</h1>
+          <h2>{error.message}</h2>
+        </>
+      )}
     </div>
   )
 }
diff --git a/apps/viewer/pages/[[...publicId]].tsx b/apps/viewer/pages/[[...publicId]].tsx
index 2a648c799..d0383f960 100644
--- a/apps/viewer/pages/[[...publicId]].tsx
+++ b/apps/viewer/pages/[[...publicId]].tsx
@@ -14,13 +14,21 @@ export const getServerSideProps: GetServerSideProps = async (
   try {
     if (!context.req.headers.host) return { props: {} }
     const viewerUrls = (process.env.NEXT_PUBLIC_VIEWER_URL ?? '').split(',')
-    typebot = viewerUrls.some((url) =>
+    const isMatchingViewerUrl = viewerUrls.some((url) =>
       context.req.headers.host?.includes(url.split('//')[1])
     )
+    const customDomain = `${context.req.headers.host}${
+      pathname === '/' ? '' : pathname
+    }`
+    typebot = isMatchingViewerUrl
       ? await getTypebotFromPublicId(context.query.publicId?.toString())
-      : await getTypebotFromCustomDomain(
-          `${context.req.headers.host}${pathname === '/' ? '' : pathname}`
-        )
+      : await getTypebotFromCustomDomain(customDomain)
+    if (!typebot)
+      console.log(
+        isMatchingViewerUrl
+          ? `Couldn't find publicId: ${context.query.publicId?.toString()}`
+          : `Couldn't customDomain: ${customDomain}`
+      )
     return {
       props: {
         typebot,