diff --git a/src/Mapper/ContactApiToEntityMapper.php b/src/Mapper/ContactApiToEntityMapper.php
index a256959..8eefd5a 100644
--- a/src/Mapper/ContactApiToEntityMapper.php
+++ b/src/Mapper/ContactApiToEntityMapper.php
@@ -35,7 +35,7 @@ class ContactApiToEntityMapper implements MapperInterface
         } else {
             $user = $this->security->getUser();
             assert($user instanceof User);
-            if ($dto->partner === null) {
+            if ($dto->partnerIri === null) {
                 throw new \Exception('Partner missing');
             }
             $partner = $this->microMapper->map($dto->partnerIri, Partner::class, [