diff --git a/backend/src/federation/authenticateCommunities.ts b/backend/src/federation/authenticateCommunities.ts
index ad2d91469..f186adb35 100644
--- a/backend/src/federation/authenticateCommunities.ts
+++ b/backend/src/federation/authenticateCommunities.ts
@@ -7,7 +7,7 @@ import { AuthenticationClient as V1_0_AuthenticationClient } from '@/federation/
 import { ensureUrlEndsWithSlash } from 'core'
 
 import { LOG4JS_BASE_CATEGORY_NAME } from '@/config/const'
-import { encryptAndSign, OpenConnectionJwtPayloadType } from 'shared'
+import { communityAuthenticatedSchema, encryptAndSign, OpenConnectionJwtPayloadType } from 'shared'
 import { getLogger } from 'log4js'
 import { AuthenticationClientFactory } from './client/AuthenticationClientFactory'
 import { EncryptedTransferArgs } from 'core'
@@ -34,13 +34,10 @@ export async function startCommunityAuthentication(
   methodLogger.debug('started with comB:', new CommunityLoggingView(comB))
   // check if communityUuid is not a valid v4Uuid
   try {
-    if (
-      comB &&
-      ((comB.communityUuid === null && comB.authenticatedAt === null) ||
-        (comB.communityUuid !== null &&
-          (!validateUUID(comB.communityUuid) ||
-          versionUUID(comB.communityUuid!) !== 4)))
-    ) {
+    // communityAuthenticatedSchema.safeParse return true 
+    // - if communityUuid is a valid v4Uuid and 
+    // - if authenticatedAt is a valid date
+    if (comB && !communityAuthenticatedSchema.safeParse(comB).success) {
       methodLogger.debug('comB.uuid is null or is a not valid v4Uuid...', comB.communityUuid || 'null', comB.authenticatedAt || 'null')
       const client = AuthenticationClientFactory.getInstance(fedComB)
 
diff --git a/backend/src/federation/validateCommunities.ts b/backend/src/federation/validateCommunities.ts
index 36c9985c9..cb56a8c53 100644
--- a/backend/src/federation/validateCommunities.ts
+++ b/backend/src/federation/validateCommunities.ts
@@ -3,6 +3,7 @@ import {
   FederatedCommunity as DbFederatedCommunity,
   FederatedCommunityLoggingView,
   getHomeCommunity,
+  getNotReachableCommunities,
 } from 'database'
 import { IsNull } from 'typeorm'
 
@@ -11,7 +12,7 @@ import { FederationClient as V1_0_FederationClient } from '@/federation/client/1
 import { PublicCommunityInfo } from '@/federation/client/1_0/model/PublicCommunityInfo'
 import { FederationClientFactory } from '@/federation/client/FederationClientFactory'
 import { LogError } from '@/server/LogError'
-import { createKeyPair } from 'shared'
+import { createKeyPair, uint32Schema } from 'shared'
 import { getLogger } from 'log4js'
 import { startCommunityAuthentication } from './authenticateCommunities'
 import { PublicCommunityInfoLoggingView } from './client/1_0/logging/PublicCommunityInfoLogging.view'
@@ -27,6 +28,16 @@ export async function startValidateCommunities(timerInterval: number): Promise<v
   // delete all foreign federated community entries to avoid increasing validation efforts and log-files
   await DbFederatedCommunity.delete({ foreign: true })
 
+  // clean community_uuid and authenticated_at fields for community with one-time-code in community_uuid field
+  const notReachableCommunities = await getNotReachableCommunities()
+  for (const community of notReachableCommunities) {
+    if (uint32Schema.safeParse(Number(community.communityUuid)).success) {
+      community.communityUuid = null
+      community.authenticatedAt = null
+      await DbCommunity.save(community)
+    }
+  }
+
   // TODO: replace the timer-loop by an event-based communication to verify announced foreign communities
   // better to use setTimeout twice than setInterval once -> see https://javascript.info/settimeout-setinterval
   setTimeout(async function run() {
diff --git a/database/src/queries/communities.ts b/database/src/queries/communities.ts
index e216f8af6..cdb7cabb6 100644
--- a/database/src/queries/communities.ts
+++ b/database/src/queries/communities.ts
@@ -60,4 +60,13 @@ export async function getReachableCommunities(
     ],
     order,
   })
+}
+
+export async function getNotReachableCommunities(
+  order?: FindOptionsOrder<DbCommunity>
+): Promise<DbCommunity[]> {
+  return await DbCommunity.find({
+    where: { authenticatedAt: IsNull(), foreign: true },
+    order,
+  })
 }
\ No newline at end of file
diff --git a/federation/src/graphql/api/1_0/resolver/AuthenticationResolver.ts b/federation/src/graphql/api/1_0/resolver/AuthenticationResolver.ts
index 84d85a0af..fd948300e 100644
--- a/federation/src/graphql/api/1_0/resolver/AuthenticationResolver.ts
+++ b/federation/src/graphql/api/1_0/resolver/AuthenticationResolver.ts
@@ -127,21 +127,27 @@ export class AuthenticationResolver {
     methodLogger.debug(`authenticate() via apiVersion=1_0 ...`, args)
     try {
       const authArgs = await interpretEncryptedTransferArgs(args) as AuthenticationJwtPayloadType
+      methodLogger.debug(`interpreted authentication payload...authArgs:`, authArgs)
       if (!authArgs) {
         const errmsg = `invalid authentication payload of requesting community with publicKey` + args.publicKey
         methodLogger.error(errmsg)
         // no infos to the caller
         return null
       }
+
       if (!uint32Schema.safeParse(Number(authArgs.oneTimeCode)).success) {
         const errmsg = `invalid oneTimeCode: ${authArgs.oneTimeCode} for community with publicKey ${authArgs.publicKey}, expect uint32`
         methodLogger.error(errmsg)
         // no infos to the caller
         return null
       }
+
+      methodLogger.debug(`search community per oneTimeCode:`, authArgs.oneTimeCode)
       const authCom = await DbCommunity.findOneByOrFail({ communityUuid: authArgs.oneTimeCode })
       if (authCom) {
         methodLogger.debug('found authCom:', new CommunityLoggingView(authCom))
+        methodLogger.debug('authCom.publicKey', authCom.publicKey.toString('hex'))
+        methodLogger.debug('args.publicKey', args.publicKey)
         if (authCom.publicKey.compare(Buffer.from(args.publicKey, 'hex')) !== 0) {
           const errmsg = `corrupt authentication call detected, oneTimeCode: ${authArgs.oneTimeCode} doesn't belong to caller: ${args.publicKey}`
           methodLogger.error(errmsg)
diff --git a/federation/src/graphql/api/1_0/util/authenticateCommunity.ts b/federation/src/graphql/api/1_0/util/authenticateCommunity.ts
index a5a3f532a..4d8af9187 100644
--- a/federation/src/graphql/api/1_0/util/authenticateCommunity.ts
+++ b/federation/src/graphql/api/1_0/util/authenticateCommunity.ts
@@ -15,6 +15,7 @@ import { randombytes_random } from 'sodium-native'
 import { AuthenticationClient as V1_0_AuthenticationClient } from '@/client/1_0/AuthenticationClient'
 import { LOG4JS_BASE_CATEGORY_NAME } from '@/config/const'
 import { AuthenticationJwtPayloadType, AuthenticationResponseJwtPayloadType, encryptAndSign, OpenConnectionCallbackJwtPayloadType, uint32Schema, uuidv4Schema, verifyAndDecrypt } from 'shared'
+import { FEDERATION_AUTHENTICATION_TIMEOUT_MS } from 'shared'
 
 const logger = getLogger(`${LOG4JS_BASE_CATEGORY_NAME}.graphql.api.1_0.util.authenticateCommunity`)
 
@@ -45,9 +46,12 @@ export async function startOpenConnectionCallback(
     if (uuidv4Schema.safeParse(comA.communityUuid).success) {
       methodLogger.debug('Community UUID is already a valid UUID')
       return
+      // check for still ongoing authentication, but with timeout
     } else if (uint32Schema.safeParse(Number(comA.communityUuid)).success) {
-      methodLogger.debug('Community UUID is still in authentication...oneTimeCode=', comA.communityUuid)
-      return
+      if (comA.updatedAt && (Date.now() - comA.updatedAt.getTime()) < FEDERATION_AUTHENTICATION_TIMEOUT_MS) {
+        methodLogger.debug('Community UUID is still in authentication...oneTimeCode=', comA.communityUuid)
+        return
+      }
     }
     // TODO: make sure it is unique
     const oneTimeCode = randombytes_random().toString()
diff --git a/shared/src/const/index.ts b/shared/src/const/index.ts
index e6fb80990..549991c61 100644
--- a/shared/src/const/index.ts
+++ b/shared/src/const/index.ts
@@ -1,4 +1,6 @@
 export const DECAY_START_TIME = new Date('2021-05-13T17:46:31Z')
 export const SECONDS_PER_YEAR_GREGORIAN_CALENDER = 31556952.0
 export const LOG4JS_BASE_CATEGORY_NAME = 'shared'
-export const REDEEM_JWT_TOKEN_EXPIRATION = '10m'
\ No newline at end of file
+export const REDEEM_JWT_TOKEN_EXPIRATION = '10m'
+// 10 minutes
+export const FEDERATION_AUTHENTICATION_TIMEOUT_MS = 60 * 60 * 1000 * 10
\ No newline at end of file
diff --git a/shared/src/index.ts b/shared/src/index.ts
index a9e070d7f..1e44e2c48 100644
--- a/shared/src/index.ts
+++ b/shared/src/index.ts
@@ -1,5 +1,6 @@
 export * from './schema'
 export * from './enum'
+export * from './const'
 export * from './helper'
 export * from './logic/decay'
 export * from './jwt/JWT'
diff --git a/shared/src/schema/community.schema.test.ts b/shared/src/schema/community.schema.test.ts
new file mode 100644
index 000000000..a46ea9c94
--- /dev/null
+++ b/shared/src/schema/community.schema.test.ts
@@ -0,0 +1,35 @@
+import { v4 as uuidv4 } from 'uuid'
+import { communityAuthenticatedSchema } from './community.schema'
+import { describe, it, expect } from 'bun:test'
+
+
+describe('communityAuthenticatedSchema', () => {
+  it('should return an error if communityUuid is not a uuidv4', () => {
+    const data = communityAuthenticatedSchema.safeParse({
+      communityUuid: '1234567890',
+      authenticatedAt: new Date(),
+    })
+
+    expect(data.success).toBe(false)
+    expect(data.error?.issues[0].path).toEqual(['communityUuid'])
+  })
+
+  it('should return an error if authenticatedAt is not a date', () => {
+    const data = communityAuthenticatedSchema.safeParse({
+      communityUuid: uuidv4(),
+      authenticatedAt: '2022-01-01',
+    })
+
+    expect(data.success).toBe(false)
+    expect(data.error?.issues[0].path).toEqual(['authenticatedAt'])
+  })
+
+  it('should return no error for valid data and valid uuid4', () => {
+    const data = communityAuthenticatedSchema.safeParse({
+      communityUuid: uuidv4(),
+      authenticatedAt: new Date(),
+    })
+
+    expect(data.success).toBe(true)
+  })
+})
diff --git a/shared/src/schema/community.schema.ts b/shared/src/schema/community.schema.ts
new file mode 100644
index 000000000..6067e3538
--- /dev/null
+++ b/shared/src/schema/community.schema.ts
@@ -0,0 +1,7 @@
+import { object, date } from 'zod'
+import { uuidv4Schema } from './base.schema'
+
+export const communityAuthenticatedSchema = object({
+  communityUuid: uuidv4Schema,
+  authenticatedAt: date(),
+})
\ No newline at end of file
diff --git a/shared/src/schema/index.ts b/shared/src/schema/index.ts
index d8c9f9e4c..83455fb73 100644
--- a/shared/src/schema/index.ts
+++ b/shared/src/schema/index.ts
@@ -1,2 +1,3 @@
 export * from './user.schema'
-export * from './base.schema'
\ No newline at end of file
+export * from './base.schema'
+export * from './community.schema'
\ No newline at end of file