How to change authentication failure response message content type in WSO2 API Manager

With WSO2 API Manager, when calling an API with an expired tokens we are getting a SOAP response like following by default, the content type is XML.

    
       
           900904
           Access Token Inactive
           Access failure for API: /Authenticate, version: 1.0.0 with key: bb50cf86703ef76d4f4c3018ca74f115
       
    

If an application is expecting JSON response, API Manager has to send JSON version of authentication failure response. You can do this by changing

to

in [API_Manager]/repository/deployment/server/synapse-configs/default/sequences/_auth_failure_handler_.xml file After the change you will get

{
    "fault": {
        "code": "900904",
        "message": "Access Token Inactive",
        "description": "Access failure for API: /weatherApi, version: 1.0.0 with key: asPZCocnJt7m6KnAqGNNPH97fdga"
    }
}