diff --git a/web/app/(shareLayout)/webapp-signin/components/external-member-sso-auth.tsx b/web/app/(shareLayout)/webapp-signin/components/external-member-sso-auth.tsx
index 6765468d5e..e9b15ae331 100644
--- a/web/app/(shareLayout)/webapp-signin/components/external-member-sso-auth.tsx
+++ b/web/app/(shareLayout)/webapp-signin/components/external-member-sso-auth.tsx
@@ -6,6 +6,7 @@ import { fetchWebOAuth2SSOUrl, fetchWebOIDCSSOUrl, fetchWebSAMLSSOUrl } from '@/
 import { useGlobalPublicStore } from '@/context/global-public-context'
 import { SSOProtocol } from '@/types/feature'
 import Loading from '@/app/components/base/loading'
+import AppUnavailable from '@/app/components/base/app-unavailable'
 
 const ExternalMemberSSOAuth = () => {
   const systemFeatures = useGlobalPublicStore(s => s.systemFeatures)
@@ -63,6 +64,12 @@ const ExternalMemberSSOAuth = () => {
     handleSSOLogin()
   }, [handleSSOLogin])
 
+  if (!systemFeatures.webapp_auth.sso_config.protocol) {
+    return <div className="flex h-full items-center justify-center">
+      <AppUnavailable code={403} unknownReason='sso protocol is invalid.' />
+    </div>
+  }
+
   return (
     <div className="flex h-full items-center justify-center">
       <Loading />