The following events can be raised by the iOS SDK. transactionCreated Returns data about the transaction object when the transaction was successfully created. 
{
  "transactionID": "8724fd24-5489-4a5d-90fd-0604df7d3b83",
  "status": "pending",
  "paymentMethodID": "17d57b9a-408d-49b8-9a97-9db382593003"
}
transactionFailed Returned when the transaction encounters an error. 
{
  "transactionID": "8724fd24-5489-4a5d-90fd-0604df7d3b83",
  "status": "pending",
  "paymentMethodID": "17d57b9a-408d-49b8-9a97-9db382593003"
}
When a network error occurs, the payload includes a responseCode. 
{
  "transactionID": "",
  "status": "",
  "paymentMethodID": null,
  "responseCode": "ETIMEDOUT",
}
Here’s a list of potential values for responseCode:
CodeDefinition
ERR_BAD_OPTION_VALUEInvalid or unsupported value provided in axios configuration.
ERR_BAD_OPTIONInvalid option provided in axios configuration.
ECONNABORTEDRequest timed out due to exceeding timeout specified in axios configuration.
ETIMEDOUTRequest timed out due to exceeding default axios time limit.
ERR_NETWORKNetwork-related issue.
ERR_FR_TOO_MANY_REDIRECTSRequest is redirected too many times; exceeds max redirects specified in axios configuration.
ERR_DEPRECATEDDeprecated feature or method used in axios.
ERR_BAD_RESPONSEResponse cannot be parsed properly or is in an unexpected format.
ERR_BAD_REQUESTRequested has unexpected format or missing required parameters.
ERR_CANCELEDFeature or method is canceled explicitly by the user.
ERR_NOT_SUPPORTFeature or method not supported in the current axios environment.
ERR_INVALID_URLInvalid URL provided for axios request.
cancelled Returned when the user closes the payment sheet without creating a transaction. generalError Returned when the SDK encounters an error. 
{
  "mattilda Pay Error: Failed to load"
}