diff --git a/api/pmt.yml b/api/pmt.yml
index c339ada..e2318d9 100644
--- a/api/pmt.yml
+++ b/api/pmt.yml
@@ -184,6 +184,8 @@ paths:
           $ref: "#/components/responses/UnprocessableContent"
         500:
           $ref: "#/components/responses/InternalError"
+        503:
+          $ref: "#/components/responses/ServiceUnavailable"
 
     delete:
       operationId: "deleteProject"
diff --git a/src/main/java/de/hmmh/pmt/ApiController.java b/src/main/java/de/hmmh/pmt/ApiController.java
index b201393..e7e702e 100644
--- a/src/main/java/de/hmmh/pmt/ApiController.java
+++ b/src/main/java/de/hmmh/pmt/ApiController.java
@@ -98,7 +98,6 @@ public class ApiController implements DefaultApi {
 
     @Override
     public ResponseEntity<Void> addEmployee(Long id, AddEmployeeDTO body) {
-
         Optional<Project> optionalProject = projectRepository.findById(id);
         if (optionalProject.isEmpty()) {
             return new ResponseEntity<>(HttpStatus.NOT_FOUND);
@@ -111,12 +110,14 @@ public class ApiController implements DefaultApi {
         } catch (HttpClientErrorException exception) {
             return new ResponseEntity<>(exception.getStatusCode().equals(HttpStatus.NOT_FOUND)
                     ? HttpStatus.NOT_FOUND
-                    : HttpStatus.INTERNAL_SERVER_ERROR);
+                    : HttpStatus.SERVICE_UNAVAILABLE);
+        } catch (RestClientException exception) {
+            return new ResponseEntity<>(HttpStatus.INTERNAL_SERVER_ERROR);
         }
 
         if (employee.getSkillSet()
                 .stream()
-                .anyMatch(qualification -> qualification.getId().equals(body.getQualificationId()))) {
+                .noneMatch(qualification -> qualification.getId().equals(body.getQualificationId()))) {
             return new ResponseEntity<>(HttpStatus.UNPROCESSABLE_ENTITY);
         }
 
@@ -141,4 +142,4 @@ public class ApiController implements DefaultApi {
 
         return new ResponseEntity<>(HttpStatus.NO_CONTENT);
     }
-}
\ No newline at end of file
+}