diff --git a/backend/src/auth/RIGHTS.ts b/backend/src/auth/RIGHTS.ts
index d5e2cc7ce..8e51c182e 100644
--- a/backend/src/auth/RIGHTS.ts
+++ b/backend/src/auth/RIGHTS.ts
@@ -48,4 +48,5 @@ export enum RIGHTS {
   LIST_CONTRIBUTION_LINKS = 'LIST_CONTRIBUTION_LINKS',
   DELETE_CONTRIBUTION_LINK = 'DELETE_CONTRIBUTION_LINK',
   UPDATE_CONTRIBUTION_LINK = 'UPDATE_CONTRIBUTION_LINK',
+  ADMIN_RETRIEVE_NOT_REGISTERED_EMAILS = 'ADMIN_RETRIEVE_NOT_REGISTERED_EMAILS',
 }
diff --git a/backend/src/graphql/resolver/KlicktippResolver.ts b/backend/src/graphql/resolver/KlicktippResolver.ts
index ce9a097e2..fecf6f08c 100644
--- a/backend/src/graphql/resolver/KlicktippResolver.ts
+++ b/backend/src/graphql/resolver/KlicktippResolver.ts
@@ -7,6 +7,8 @@ import {
 } from '@/apis/KlicktippController'
 import { RIGHTS } from '@/auth/RIGHTS'
 import SubscribeNewsletterArgs from '@arg/SubscribeNewsletterArgs'
+import { User } from '@entity/User'
+import { backendLogger } from '@/server/logger'
 
 @Resolver()
 export class KlicktippResolver {
@@ -35,4 +37,21 @@ export class KlicktippResolver {
   ): Promise<boolean> {
     return await klicktippSignIn(email, language)
   }
+
+  @Authorized([RIGHTS.ADMIN_RETRIEVE_NOT_REGISTERED_EMAILS])
+  @Query(() => [String])
+  async retrieveNotRegisteredEmails(): Promise<string[]> {
+    const users = await User.find()
+    const notRegisteredUser = []
+    for (let i = 0; i < users.length; i++) {
+      const user = users[i]
+      try {
+        await getKlickTippUser(user.email)
+      } catch (err) {
+        notRegisteredUser.push(user.email)
+        backendLogger.error(`Error with email: ${user.email}; ${err}`)
+      }
+    }
+    return notRegisteredUser
+  }
 }