The error response from the API can be read as follows:

{
    // Generic errors are populated in the `_errors` or `errors` fields.
    _errors: [],
    errors: string,

    // Specific errors regarding the input params are formatted as:
    //   key = name of the parameter
    //   value = the error message or messages associated with the parameter
    contractType: {_errors: [""]} | string,
    chain: {_errors: [""]} | string
}