In case of unsuccessful request execution a Fail status will be returned along with appropriate error message. List of common error messages is presented below; those not listed are related to specific method category which they are part of.
API Key permissions are not sufficient to perform given action.
API-Hash signature is not valid.
Response time was exceeded.
Invalid: parameters / request type / path.
Action was blocked on user account.
Action limit was exceeded. You need to wait one minute before making another request.
The exchange is currently under maintenance. You will get also additional field: estimatedTime in Unix Timestamp and it is the time when works will be done.