Force REST API - giving below exception

[sagarjamage7714]

java.lang.RuntimeException: com.fasterxml.jackson.databind.JsonMappingException: No content to map due to end-of-input at [Source: UNKNOWN; line: 1, column: 1] java.lang.RuntimeException: com.fasterxml.jackson.databind.JsonMappingException: No content to map due to end-of-input at [Source: UNKNOWN; line: 1, column: 1] at com.force.api.Auth.oauthLoginPasswordFlow(Auth.java:47) at com.force.api.Auth.authenticate(Auth.java:208) at com.force.api.ForceApi.(ForceApi.java:68) at com.aws.datasync.SalesforceConnector.main(SalesforceConnector.java:23) Caused by: com.fasterxml.jackson.databind.JsonMappingException: No content to map due to end-of-input at [Source: UNKNOWN; line: 1, column: 1] at com.fasterxml.jackson.databind.JsonMappingException.from(JsonMappingException.java:148) at com.fasterxml.jackson.databind.ObjectMapper._initForReading(ObjectMapper.java:3607) at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:3547) at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:2648) at com.force.api.Auth.oauthLoginPasswordFlow(Auth.java:32) ... 3 more