diff --git a/backend/src/graphql/resolver/ProjectBrandingResolver.ts b/backend/src/graphql/resolver/ProjectBrandingResolver.ts
index edfe3eef2..2c3b5a08d 100644
--- a/backend/src/graphql/resolver/ProjectBrandingResolver.ts
+++ b/backend/src/graphql/resolver/ProjectBrandingResolver.ts
@@ -11,6 +11,7 @@ import {
   projectBrandingsTable,
 } from 'database'
 import { getLogger } from 'log4js'
+import { projectBrandingSchema } from 'shared'
 import { Arg, Authorized, ID, Int, Mutation, Query, Resolver } from 'type-graphql'
 import { HumHubClient } from '@/apis/humhub/HumHubClient'
 import { RIGHTS } from '@/auth/RIGHTS'
@@ -50,7 +51,7 @@ export class ProjectBrandingResolver {
   async upsertProjectBranding(
     @Arg('input') input: ProjectBrandingInput,
   ): Promise<ProjectBranding | null> {
-    return new ProjectBranding(await dbUpsertProjectBranding(input))
+    return new ProjectBranding(await dbUpsertProjectBranding(projectBrandingSchema.parse(input)))
   }
 
   @Mutation(() => Boolean)
diff --git a/backend/src/graphql/resolver/UserResolver.ts b/backend/src/graphql/resolver/UserResolver.ts
index 061498207..fb2481446 100644
--- a/backend/src/graphql/resolver/UserResolver.ts
+++ b/backend/src/graphql/resolver/UserResolver.ts
@@ -30,9 +30,11 @@ import {
   TransactionLink as DbTransactionLink,
   User as DbUser,
   UserContact as DbUserContact,
+  dbFindProjectBrandingByAlias,
+  dbFindProjectSpaceId,
   findUserByIdentifier,
   getHomeCommunity,
-  ProjectBranding,
+  ProjectBrandingSelect,
   UserLoggingView,
 } from 'database'
 import { GraphQLResolveInfo } from 'graphql'
@@ -202,7 +204,7 @@ export class UserResolver {
 
     // request to humhub and klicktipp run in parallel
     let humhubUserPromise: Promise<IRestResponse<GetUser>> | undefined
-    let projectBrandingPromise: Promise<ProjectBranding | null> | undefined
+    let projectBrandingSpaceIdPromise: Promise<number | null | undefined> | undefined
     const klicktippStatePromise = getKlicktippState(dbUser.emailContact.email)
     if (CONFIG.HUMHUB_ACTIVE && dbUser.humhubAllowed) {
       const getHumhubUser = new PostUser(dbUser)
@@ -211,10 +213,7 @@ export class UserResolver {
       )
     }
     if (project) {
-      projectBrandingPromise = ProjectBranding.findOne({
-        where: { alias: project },
-        select: { spaceId: true },
-      })
+      projectBrandingSpaceIdPromise = dbFindProjectSpaceId(project)
     }
 
     if (
@@ -244,19 +243,15 @@ export class UserResolver {
     })
 
     await EVENT_USER_LOGIN(dbUser)
-    const projectBranding = await projectBrandingPromise
-    logger.debug('project branding: ', projectBranding?.id)
+    const projectBrandingSpaceId = await projectBrandingSpaceIdPromise
+    logger.debug('project branding: ', projectBrandingSpaceId)
     // load humhub state
     if (humhubUserPromise) {
       try {
         const result = await humhubUserPromise
         user.humhubAllowed = result?.result?.account.status === 1
         if (user.humhubAllowed && result?.result?.account?.username) {
-          let spaceId = null
-          if (projectBranding) {
-            spaceId = projectBranding.spaceId
-          }
-          await syncHumhub(null, dbUser, result.result.account.username, spaceId)
+          await syncHumhub(null, dbUser, result.result.account.username, projectBrandingSpaceId)
         }
       } catch (e) {
         logger.error("couldn't reach out to humhub, disable for now", e)
@@ -359,12 +354,9 @@ export class UserResolver {
         return user
       }
     }
-    let projectBrandingPromise: Promise<ProjectBranding | null> | undefined
+    let projectBrandingPromise: Promise<ProjectBrandingSelect | undefined> | undefined
     if (project) {
-      projectBrandingPromise = ProjectBranding.findOne({
-        where: { alias: project },
-        select: { logoUrl: true, spaceId: true },
-      })
+      projectBrandingPromise = dbFindProjectBrandingByAlias(project)
     }
     const gradidoID = await newGradidoID(logger)
 
@@ -423,7 +415,7 @@ export class UserResolver {
     const queryRunner = db.getDataSource().createQueryRunner()
     await queryRunner.connect()
     await queryRunner.startTransaction('REPEATABLE READ')
-    let projectBranding: ProjectBranding | null | undefined
+    let projectBranding: ProjectBrandingSelect | undefined
     try {
       dbUser = await queryRunner.manager.save(dbUser).catch((error) => {
         throw new LogError('Error while saving dbUser', error)
@@ -924,7 +916,9 @@ export class UserResolver {
     }
     // should rarely happen, so we don't optimize for parallel processing
     if (!dbUser.humhubAllowed && project) {
-      await ProjectBranding.findOneOrFail({ where: { alias: project } })
+      if (!(await dbFindProjectBrandingByAlias(project))) {
+        throw new LogError(`project branding with alias: ${project} not found`)
+      }
       dbUser.humhubAllowed = true
       await dbUser.save()
     }
diff --git a/backend/src/graphql/resolver/util/syncHumhub.ts b/backend/src/graphql/resolver/util/syncHumhub.ts
index 7fbca18ce..9f1556ce5 100644
--- a/backend/src/graphql/resolver/util/syncHumhub.ts
+++ b/backend/src/graphql/resolver/util/syncHumhub.ts
@@ -22,7 +22,7 @@ export async function syncHumhub(
   updateUserInfosArg: UpdateUserInfosArgs | null,
   user: User,
   oldHumhubUsername: string,
-  spaceId?: number | null,
+  spaceId?: number | null | undefined,
 ): Promise<GetUser | null | undefined> {
   const logger = createLogger()
   logger.addContext('user', user.id)
diff --git a/database/src/queries/projectBranding.ts b/database/src/queries/projectBranding.ts
index 3583c7e1e..4ea33a84f 100644
--- a/database/src/queries/projectBranding.ts
+++ b/database/src/queries/projectBranding.ts
@@ -56,6 +56,15 @@ export async function dbFindProjectSpaceUrl(alias: string): Promise<string | nul
     .limit(1)
   return result.at(0)?.spaceUrl
 }
+
+export async function dbFindProjectSpaceId(alias: string): Promise<number | null | undefined> {
+  const result = await drizzleDb()
+    .select({ spaceId: projectBrandingsTable.spaceId })
+    .from(projectBrandingsTable)
+    .where(eq(projectBrandingsTable.alias, alias))
+    .limit(1)
+  return result.at(0)?.spaceId
+}
 /**
  *
  * @param alias throw if project not found
@@ -91,6 +100,17 @@ export async function dbFindProjectBrandingById(
   return result.at(0)
 }
 
+export async function dbFindProjectBrandingByAlias(
+  alias: string,
+): Promise<ProjectBrandingSelect | undefined> {
+  const result = await drizzleDb()
+    .select()
+    .from(projectBrandingsTable)
+    .where(eq(projectBrandingsTable.alias, alias))
+    .limit(1)
+  return result.at(0)
+}
+
 export async function dbDeleteProjectBranding(id: number): Promise<void> {
   await drizzleDb().delete(projectBrandingsTable).where(eq(projectBrandingsTable.id, id))
 }