Merge pull request #69 from NHSDigital/APM-000-AMP-941-API-Specs---add-Errors-section

APM-000 AMP-941 API Specs - add Errors section

Author: matt-mercer

specification/mesh-api.yaml

@@ -332,7 +332,14 @@ info:
     ### Message expiration
     Messages that are not downloaded and acknowledged within five days of delivery are removed from your inbox. The sending organisation receives an error report explaining that the receiver did not collect the message. Uncollected messages are completely deleted from the MESH server 30 days after the initial delivery. If the sending organisation cannot re-send the message within the intervening time, it may contact the [NHS Digital national service desk](https://digital.nhs.uk/developer/help-and-support) with the error report details and ask for the message to be placed in your inbox again.
 
+    ## Errors
+    We use standard HTTP status codes to show whether an API request succeeded or not. They are usually in the range:
 
+    * 200 to 299 if it succeeded, including code 202 if it was accepted by an API that needs to wait for further action
+    * 400 to 499 if it failed because of a client error by your application
+    * 500 to 599 if it failed because of an error on our server
+
+    Errors specific to each API are shown in the Endpoints section, under Response. See our [reference guide](https://digital.nhs.uk/developer/guides-and-documentation/reference-guide#http-status-codes) for more on errors.
 
   title: Message Exchange for Social Care and Health - REST API
   version: v1.0.168-alpha