diff --git a/spec/file_translation/fts_common.yaml b/spec/file_translation/fts_common.yaml
index c9de7969..b694a179 100644
--- a/spec/file_translation/fts_common.yaml
+++ b/spec/file_translation/fts_common.yaml
@@ -92,6 +92,7 @@ components:
         - response
     Error:
       type: object
+      nullable: true
       properties:
         key:
           description: Error key
diff --git a/spec/file_translation/fts_language_detection.yaml b/spec/file_translation/fts_language_detection.yaml
index c121fea6..06948783 100644
--- a/spec/file_translation/fts_language_detection.yaml
+++ b/spec/file_translation/fts_language_detection.yaml
@@ -37,11 +37,11 @@ x-paths:
                     response:
                       code: VALIDATION_ERROR
                       errors:
-                        key: not.found
-                        message: >-
-                          fileUid h5dhjbg1ganp not found
-                        details:
-                          field: "fileUid"
+                        - key: not.found
+                          message: >-
+                            fileUid h5dhjbg1ganp not found
+                          details:
+                            field: "fileUid"
 
         401:
           $ref: '../api_common.yaml#/components/responses/Error401ResponseDefinition'
diff --git a/spec/file_translation/fts_mt.yaml b/spec/file_translation/fts_mt.yaml
index 2863adaa..2170ecb5 100644
--- a/spec/file_translation/fts_mt.yaml
+++ b/spec/file_translation/fts_mt.yaml
@@ -216,11 +216,11 @@ x-paths:
                     response:
                       code: VALIDATION_ERROR
                       errors:
-                        key: locale.not.requested
-                        message: >-
-                          Processing request did not contain locale de-DE
-                        details:
-                          field: "localeId"
+                        - key: locale.not.requested
+                          message: >-
+                            Processing request did not contain locale de-DE
+                          details:
+                            field: "localeId"
         '401':
           $ref: '../api_common.yaml#/components/responses/Error401ResponseDefinition'
         '429':
@@ -274,6 +274,7 @@ x-paths:
                 type: string
                 format: binary
         400:
+          description: "Validation error"
           content:
             application/json:
               schema:
@@ -284,11 +285,11 @@ x-paths:
                     response:
                       code: VALIDATION_ERROR
                       errors:
-                        key: mt.not.completed
-                        message: >-
-                          State of processing is QUEUED. Only COMPLETED,CANCELED allow final file to be downloaded
-                        details:
-                          field: "mtUid"
+                        - key: mt.not.completed
+                          message: >-
+                            State of processing is QUEUED. Only COMPLETED,CANCELED allow final file to be downloaded
+                          details:
+                            field: "mtUid"
         401:
           $ref: '../api_common.yaml#/components/responses/Error401ResponseDefinition'
         429:
@@ -341,18 +342,20 @@ components:
                     error:
                       $ref: './fts_common.yaml#/components/schemas/Error'
                     localeProcessStatuses:
-                      type: object
-                      properties:
-                        localeId:
-                          type: string
-                          description: Locale, requested for translation
-                        state:
-                          $ref: '#/components/schemas/MTState'
-                        processedStringCount:
-                          type: integer
-                          description: Amount of strings translated for the locale
-                        error:
-                          $ref: './fts_common.yaml#/components/schemas/Error'
+                      type: array
+                      items:
+                        type: object
+                        properties:
+                          localeId:
+                            type: string
+                            description: Locale, requested for translation
+                          state:
+                            $ref: '#/components/schemas/MTState'
+                          processedStringCount:
+                            type: integer
+                            description: Amount of strings translated for the locale
+                          error:
+                            $ref: './fts_common.yaml#/components/schemas/Error'
                   type: object
 
               type: object