diff --git a/backend/src/graphql/resolver/UserResolver.ts b/backend/src/graphql/resolver/UserResolver.ts
index 056cf15c2..e50f4768d 100644
--- a/backend/src/graphql/resolver/UserResolver.ts
+++ b/backend/src/graphql/resolver/UserResolver.ts
@@ -168,7 +168,9 @@ export class UserResolver {
     let humhubUserPromise: Promise<IRestResponse<GetUser>> | undefined
     const klicktippStatePromise = getKlicktippState(dbUser.emailContact.email)
     if (CONFIG.HUMHUB_ACTIVE && dbUser.humhubAllowed) {
-      humhubUserPromise = HumHubClient.getInstance()?.userByUsernameAsync(email)
+      humhubUserPromise = HumHubClient.getInstance()?.userByUsernameAsync(
+        dbUser.alias && dbUser.gradidoID,
+      )
     }
 
     if (dbUser.passwordEncryptionType !== PasswordEncryptionType.GRADIDO_ID) {
@@ -727,7 +729,10 @@ export class UserResolver {
       throw new LogError('cannot create humhub client')
     }
     const username = dbUser.alias ?? dbUser.gradidoID
-    const humhubUser = await humhubClient.userByUsername(username)
+    let humhubUser = await humhubClient.userByUsername(username)
+    if (!humhubUser) {
+      humhubUser = await humhubClient.userByEmail(dbUser.emailContact.email)
+    }
     if (!humhubUser) {
       throw new LogError("user don't exist (any longer) on humhub")
     }
diff --git a/backend/src/graphql/resolver/util/syncHumhub.ts b/backend/src/graphql/resolver/util/syncHumhub.ts
index 73ec755ee..426f89c92 100644
--- a/backend/src/graphql/resolver/util/syncHumhub.ts
+++ b/backend/src/graphql/resolver/util/syncHumhub.ts
@@ -28,7 +28,10 @@ export async function syncHumhub(
     return
   }
   logger.debug('retrieve user from humhub')
-  const humhubUser = await humhubClient.userByUsername(user.alias ?? user.gradidoID)
+  let humhubUser = await humhubClient.userByUsername(user.alias ?? user.gradidoID)
+  if (!humhubUser) {
+    humhubUser = await humhubClient.userByEmail(user.emailContact.email)
+  }
   const humhubUsers = new Map<string, GetUser>()
   if (humhubUser) {
     humhubUsers.set(user.emailContact.email, humhubUser)
diff --git a/frontend/src/components/Menu/Sidebar.spec.js b/frontend/src/components/Menu/Sidebar.spec.js
index de11f1041..8891d0516 100644
--- a/frontend/src/components/Menu/Sidebar.spec.js
+++ b/frontend/src/components/Menu/Sidebar.spec.js
@@ -1,8 +1,12 @@
 import { mount } from '@vue/test-utils'
 import Sidebar from './Sidebar'
+import CONFIG from '../../config'
 
 const localVue = global.localVue
 
+CONFIG.GMS_ACTIVE = 'true'
+CONFIG.HUMHUB_ACTIVE = 'true'
+
 describe('Sidebar', () => {
   let wrapper
 
diff --git a/frontend/src/components/Menu/Sidebar.vue b/frontend/src/components/Menu/Sidebar.vue
index ade0aad29..e71fdbfeb 100644
--- a/frontend/src/components/Menu/Sidebar.vue
+++ b/frontend/src/components/Menu/Sidebar.vue
@@ -28,11 +28,11 @@
             <b-img src="/img/svg/info.svg" height="20" class="svg-icon" />
             <span class="ml-2">{{ $t('navigation.info') }}</span>
           </b-nav-item>
-          <b-nav-item to="/circles" class="mb-3" active-class="activeRoute">
+          <b-nav-item to="/circles" :class="humhubClass" active-class="activeRoute">
             <b-img src="/img/svg/circles.svg" height="20" class="svg-icon" />
             <span class="ml-2">{{ $t('navigation.circles') }}</span>
           </b-nav-item>
-          <b-nav-item to="/usersearch" active-class="activeRoute">
+          <b-nav-item to="/usersearch" :class="GMSClass" active-class="activeRoute">
             <b-img src="/img/loupe.png" height="20" />
             <span class="ml-2">{{ $t('navigation.usersearch') }}</span>
           </b-nav-item>
@@ -77,6 +77,8 @@
   </div>
 </template>
 <script>
+import CONFIG from '../../config'
+
 export default {
   name: 'Sidebar',
   props: {
@@ -89,6 +91,19 @@ export default {
       }
       return 'mb-3'
     },
+    humhubClass() {
+      if (CONFIG.HUMHUB_ACTIVE === 'true') {
+        return 'mb-3'
+      } else {
+        return 'invisible'
+      }
+    },
+    GMSClass() {
+      if (CONFIG.GMS_ACTIVE !== 'true') {
+        return 'invisible'
+      }
+      return ''
+    },
   },
 }
 </script>
@@ -109,6 +124,9 @@ export default {
   filter: brightness(0) invert(0);
 }
 
+.invisible {
+  display: none;
+}
 #component-sidebar {
   min-width: 200px;
 }
diff --git a/frontend/src/pages/Settings.vue b/frontend/src/pages/Settings.vue
index 8a0a39f8d..2116bcdf9 100644
--- a/frontend/src/pages/Settings.vue
+++ b/frontend/src/pages/Settings.vue
@@ -116,20 +116,19 @@
           <div v-if="isGMS" class="mt-3">
             <b-row>
               <b-col cols="12" md="6" lg="6">
-                <div class="h3 text-muted">{{ $t('GMS.title') }}</div>
+                <div class="h3">{{ $t('GMS.title') }}</div>
               </b-col>
               <b-col cols="12" md="6" lg="6" class="text-right">
                 <user-settings-switch
                   @valueChanged="gmsStateSwitch"
                   :initialValue="$store.state.gmsAllowed"
                   :attrName="'gmsAllowed'"
-                  :disabled="true"
                   :enabledText="$t('settings.GMS.enabled')"
                   :disabledText="$t('settings.GMS.disabled')"
                 />
               </b-col>
             </b-row>
-            <div class="h4 mt-3 text-muted">{{ $t('GMS.desc') }}</div>
+            <div class="h4 mt-3">{{ $t('GMS.desc') }}</div>
             <div v-if="gmsAllowed">
               <b-row class="mb-4">
                 <b-col cols="12" md="6" lg="6">
@@ -161,6 +160,17 @@
               </b-row>
             </div>
           </div>
+          <div v-else>
+            <b-row>
+              <b-col cols="12" md="6" lg="6">
+                <div class="h3 text-muted">{{ $t('GMS.title') }}</div>
+              </b-col>
+              <b-col cols="12" md="6" lg="6" class="text-right">
+                <user-settings-switch :disabled="true" />
+              </b-col>
+            </b-row>
+            <div class="h4 mt-3 text-muted">{{ $t('GMS.desc') }}</div>
+          </div>
         </b-tab>
       </div>
     </b-tabs>
@@ -241,16 +251,16 @@ export default {
       return firstName === this.firstName && lastName === this.lastName
     },
     isHumhubActivated() {
-      return this.humhubAllowed
+      return this.humhubAllowed === true
     },
     isCommunityService() {
       return this.isGMS || this.isHumhub
     },
     isGMS() {
-      return CONFIG.GMS_ACTIVE
+      return CONFIG.GMS_ACTIVE === 'true'
     },
     isHumhub() {
-      return CONFIG.HUMHUB_ACTIVE
+      return CONFIG.HUMHUB_ACTIVE === 'true'
     },
   },
   // TODO: watch: {