diff --git a/apps/provisioning_api/lib/Controller/UsersController.php b/apps/provisioning_api/lib/Controller/UsersController.php
index ba9c260224ce5..9cf232d46d0ef 100644
--- a/apps/provisioning_api/lib/Controller/UsersController.php
+++ b/apps/provisioning_api/lib/Controller/UsersController.php
@@ -536,10 +536,16 @@ public function addUser(
 			throw new OCSException($this->l10n->t('Required email address was not provided'), 110);
 		}
 
+		// Create the user
 		try {
 			$newUser = $this->userManager->createUser($userid, $password);
-			$this->logger->info('Successful addUser call with userid: ' . $userid, ['app' => 'ocs_api']);
+			if (!$newUser instanceof IUser) {
+				// If the user is not an instance of IUser, it means the user creation failed
+				$this->logger->error('Failed addUser attempt: User creation failed.', ['app' => 'ocs_api']);
+				throw new OCSException($this->l10n->t('User creation failed'), 111);
+			}
 
+			$this->logger->info('Successful addUser call with userid: ' . $userid, ['app' => 'ocs_api']);
 			foreach ($groups as $group) {
 				$this->groupManager->get($group)->addUser($newUser);
 				$this->logger->info('Added userid ' . $userid . ' to group ' . $group, ['app' => 'ocs_api']);
diff --git a/apps/provisioning_api/tests/Controller/UsersControllerTest.php b/apps/provisioning_api/tests/Controller/UsersControllerTest.php
index 8240e968abb69..05553d6b3e9aa 100644
--- a/apps/provisioning_api/tests/Controller/UsersControllerTest.php
+++ b/apps/provisioning_api/tests/Controller/UsersControllerTest.php
@@ -466,7 +466,8 @@ public function testAddUserSuccessful() {
 		$this->userManager
 			->expects($this->once())
 			->method('createUser')
-			->with('NewUser', 'PasswordOfTheNewUser');
+			->with('NewUser', 'PasswordOfTheNewUser')
+			->willReturn($this->createMock(IUser::class));
 		$this->logger
 			->expects($this->once())
 			->method('info')
@@ -529,7 +530,8 @@ public function testAddUserSuccessfulWithDisplayName() {
 		$this->userManager
 			->expects($this->once())
 			->method('createUser')
-			->with('NewUser', 'PasswordOfTheNewUser');
+			->with('NewUser', 'PasswordOfTheNewUser')
+			->willReturn($this->createMock(IUser::class));
 		$this->logger
 			->expects($this->once())
 			->method('info')
@@ -579,7 +581,8 @@ public function testAddUserSuccessfulGenerateUserID() {
 		$this->userManager
 			->expects($this->once())
 			->method('createUser')
-			->with($this->anything(), 'PasswordOfTheNewUser');
+			->with($this->anything(), 'PasswordOfTheNewUser')
+			->willReturn($this->createMock(IUser::class));
 		$this->logger
 			->expects($this->once())
 			->method('info')