diff --git a/backend/.env.dist b/backend/.env.dist
index 82f489f6c..bdb3d3892 100644
--- a/backend/.env.dist
+++ b/backend/.env.dist
@@ -27,7 +27,7 @@ DLT_CONNECTOR_URL=http://localhost:6010
 
 # Community
 COMMUNITY_NAME=Gradido Entwicklung
-COMMUNITY_URL=http://localhost/
+COMMUNITY_URL=http://localhost
 COMMUNITY_REGISTER_PATH=/register
 COMMUNITY_REDEEM_PATH=/redeem/{code}
 COMMUNITY_REDEEM_CONTRIBUTION_PATH=/redeem/CL-{code}
diff --git a/backend/src/graphql/resolver/TransactionResolver.test.ts b/backend/src/graphql/resolver/TransactionResolver.test.ts
index d130a802e..97e210dfa 100644
--- a/backend/src/graphql/resolver/TransactionResolver.test.ts
+++ b/backend/src/graphql/resolver/TransactionResolver.test.ts
@@ -142,7 +142,11 @@ describe('send coins', () => {
     })
 
     it('logs the error thrown', () => {
-      expect(logger.error).toBeCalledWith('No user with this credentials', 'wrong@email.com')
+      expect(logger.error).toBeCalledWith(
+        'No user with this credentials',
+        'wrong@email.com',
+        homeCom.communityUuid,
+      )
     })
 
     describe('deleted recipient', () => {
@@ -165,13 +169,17 @@ describe('send coins', () => {
           }),
         ).toEqual(
           expect.objectContaining({
-            errors: [new GraphQLError('No user to given contact')],
+            errors: [new GraphQLError('No user with this credentials')],
           }),
         )
       })
 
       it('logs the error thrown', () => {
-        expect(logger.error).toBeCalledWith('No user to given contact', 'stephen@hawking.uk')
+        expect(logger.error).toBeCalledWith(
+          'No user with this credentials',
+          'stephen@hawking.uk',
+          homeCom.communityUuid,
+        )
       })
     })
 
@@ -204,6 +212,7 @@ describe('send coins', () => {
         expect(logger.error).toBeCalledWith(
           'No user with this credentials',
           'garrick@ollivander.com',
+          homeCom.communityUuid,
         )
       })
     })
diff --git a/backend/src/graphql/resolver/UserResolver.test.ts b/backend/src/graphql/resolver/UserResolver.test.ts
index e16e0f0fc..d8df20585 100644
--- a/backend/src/graphql/resolver/UserResolver.test.ts
+++ b/backend/src/graphql/resolver/UserResolver.test.ts
@@ -2552,6 +2552,7 @@ describe('UserResolver', () => {
             query: userQuery,
             variables: {
               identifier: 'identifier',
+              communityIdentifier: 'community identifier',
             },
           }),
         ).resolves.toEqual(
@@ -2637,13 +2638,11 @@ describe('UserResolver', () => {
             }),
           ).resolves.toEqual(
             expect.objectContaining({
-              errors: [
-                new GraphQLError('Found user to given contact, but belongs to other community'),
-              ],
+              errors: [new GraphQLError('No user with this credentials')],
             }),
           )
           expect(logger.error).toBeCalledWith(
-            'Found user to given contact, but belongs to other community',
+            'No user with this credentials',
             'bibi@bloxberg.de',
             foreignCom1.communityUuid,
           )
diff --git a/backend/src/graphql/resolver/UserResolver.ts b/backend/src/graphql/resolver/UserResolver.ts
index 6079ac634..e3b323f8a 100644
--- a/backend/src/graphql/resolver/UserResolver.ts
+++ b/backend/src/graphql/resolver/UserResolver.ts
@@ -65,7 +65,7 @@ import random from 'random-bigint'
 import { randombytes_random } from 'sodium-native'
 
 import { FULL_CREATION_AVAILABLE } from './const/const'
-import { getCommunityName, getHomeCommunity } from './util/communities'
+import { getHomeCommunity } from './util/communities'
 import { getUserCreations } from './util/creations'
 import { findUserByIdentifier } from './util/findUserByIdentifier'
 import { findUsers } from './util/findUsers'
@@ -428,7 +428,7 @@ export class UserResolver {
     const userContact = await DbUserContact.findOneOrFail({
       where: { emailVerificationCode: code },
       relations: ['user'],
-    }).catch((e) => {
+    }).catch(() => {
       throw new LogError('Could not login with emailVerificationCode')
     })
     logger.debug('userContact loaded...')
diff --git a/backend/src/graphql/resolver/semaphore.test.ts b/backend/src/graphql/resolver/semaphore.test.ts
index dc6c5b364..ed58d55ec 100644
--- a/backend/src/graphql/resolver/semaphore.test.ts
+++ b/backend/src/graphql/resolver/semaphore.test.ts
@@ -6,6 +6,7 @@ import { Community as DbCommunity } from '@entity/Community'
 import { ApolloServerTestClient } from 'apollo-server-testing'
 import { Decimal } from 'decimal.js-light'
 import { GraphQLError } from 'graphql'
+import { v4 as uuidv4 } from 'uuid'
 
 import { cleanDB, testEnvironment, contributionDateFormatter } from '@test/helpers'
 
@@ -54,7 +55,7 @@ describe('semaphore', () => {
   beforeAll(async () => {
     const now = new Date()
     homeCom = DbCommunity.create()
-    homeCom.communityUuid = 'homeCom-UUID'
+    homeCom.communityUuid = uuidv4()
     homeCom.creationDate = new Date('2000-01-01')
     homeCom.description = 'homeCom description'
     homeCom.foreign = false
diff --git a/backend/src/graphql/resolver/util/findUserByIdentifier.ts b/backend/src/graphql/resolver/util/findUserByIdentifier.ts
index 633049afb..7e52327d3 100644
--- a/backend/src/graphql/resolver/util/findUserByIdentifier.ts
+++ b/backend/src/graphql/resolver/util/findUserByIdentifier.ts
@@ -41,14 +41,11 @@ export const findUserByIdentifier = async (
           community: communityWhere,
         },
       },
-      relations: ['user', 'user.community'],
+      relations: { user: { community: true } },
     })
     if (!userContact) {
       throw new LogError('No user with this credentials', identifier, communityIdentifier)
     }
-    if (!userContact.user) {
-      throw new LogError('No user to given contact', identifier, communityIdentifier)
-    }
     user = userContact.user
     user.emailContact = userContact
   } else if (VALID_ALIAS_REGEX.exec(identifier)) {
diff --git a/backend/src/graphql/resolver/util/findUserByIdentifiers.test.ts b/backend/src/graphql/resolver/util/findUserByIdentifiers.test.ts
new file mode 100644
index 000000000..cfdbce8f2
--- /dev/null
+++ b/backend/src/graphql/resolver/util/findUserByIdentifiers.test.ts
@@ -0,0 +1,94 @@
+/* eslint-disable @typescript-eslint/no-unsafe-member-access */
+/* eslint-disable @typescript-eslint/no-unsafe-assignment */
+/* eslint-disable @typescript-eslint/restrict-template-expressions */
+import { Connection } from '@dbTools/typeorm'
+import { Community as DbCommunity } from '@entity/Community'
+import { User as DbUser } from '@entity/User'
+import { ApolloServerTestClient } from 'apollo-server-testing'
+
+import { cleanDB, testEnvironment } from '@test/helpers'
+
+import { writeHomeCommunityEntry } from '@/seeds/community'
+import { userFactory } from '@/seeds/factory/user'
+import { bibiBloxberg } from '@/seeds/users/bibi-bloxberg'
+import { bobBaumeister } from '@/seeds/users/bob-baumeister'
+import { peterLustig } from '@/seeds/users/peter-lustig'
+
+import { findUserByIdentifier } from './findUserByIdentifier'
+
+let con: Connection
+let testEnv: {
+  mutate: ApolloServerTestClient['mutate']
+  query: ApolloServerTestClient['query']
+  con: Connection
+}
+
+beforeAll(async () => {
+  testEnv = await testEnvironment()
+  con = testEnv.con
+  await cleanDB()
+})
+
+afterAll(async () => {
+  await cleanDB()
+  await con.close()
+})
+
+describe('graphql/resolver/util/findUserByIdentifier', () => {
+  let homeCom: DbCommunity
+  let communityUuid: string
+  let communityName: string
+  let userBibi: DbUser
+
+  beforeAll(async () => {
+    homeCom = await writeHomeCommunityEntry()
+    // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
+    communityUuid = homeCom.communityUuid!
+    // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
+    communityName = homeCom.communityUuid!
+
+    userBibi = await userFactory(testEnv, bibiBloxberg)
+    await userFactory(testEnv, peterLustig)
+    await userFactory(testEnv, bobBaumeister)
+  })
+
+  describe('communityIdentifier is community uuid', () => {
+    it('userIdentifier is gradido id', async () => {
+      const user = await findUserByIdentifier(userBibi.gradidoID, communityUuid)
+      user.userRoles = []
+      expect(user).toMatchObject(userBibi)
+    })
+
+    it('userIdentifier is alias', async () => {
+      const user = await findUserByIdentifier(userBibi.alias, communityUuid)
+      user.userRoles = []
+      expect(user).toMatchObject(userBibi)
+    })
+
+    it('userIdentifier is email', async () => {
+      const user = await findUserByIdentifier(userBibi.emailContact.email, communityUuid)
+      user.userRoles = []
+      expect(user).toMatchObject(userBibi)
+    })
+  })
+
+  describe('communityIdentifier is community name', () => {
+    it('userIdentifier is gradido id', async () => {
+      const user = await findUserByIdentifier(userBibi.gradidoID, communityName)
+      user.userRoles = []
+      expect(user).toMatchObject(userBibi)
+    })
+
+    it('userIdentifier is alias', async () => {
+      const user = await findUserByIdentifier(userBibi.alias, communityName)
+      user.userRoles = []
+      expect(user).toMatchObject(userBibi)
+    })
+
+    it('userIdentifier is email', async () => {
+      const user = await findUserByIdentifier(userBibi.emailContact.email, communityName)
+      user.userRoles = []
+      expect(user).toMatchObject(userBibi)
+    })
+  })
+})
diff --git a/backend/src/seeds/graphql/queries.ts b/backend/src/seeds/graphql/queries.ts
index 4bd5008d3..2daa5e8bd 100644
--- a/backend/src/seeds/graphql/queries.ts
+++ b/backend/src/seeds/graphql/queries.ts
@@ -370,7 +370,7 @@ export const adminListContributionMessages = gql`
 `
 
 export const user = gql`
-  query ($identifier: String!, $communityIdentifier: String) {
+  query ($identifier: String!, $communityIdentifier: String!) {
     user(identifier: $identifier, communityIdentifier: $communityIdentifier) {
       firstName
       lastName
diff --git a/backend/src/seeds/users/bibi-bloxberg.ts b/backend/src/seeds/users/bibi-bloxberg.ts
index 7c372848e..9a40e922b 100644
--- a/backend/src/seeds/users/bibi-bloxberg.ts
+++ b/backend/src/seeds/users/bibi-bloxberg.ts
@@ -4,6 +4,7 @@ export const bibiBloxberg: UserInterface = {
   email: 'bibi@bloxberg.de',
   firstName: 'Bibi',
   lastName: 'Bloxberg',
+  alias: 'BBB',
   // description: 'Hex Hex',
   emailChecked: true,
   language: 'de',