When I try to register device that is pending for approval I get the error:
E00055: The mobile device has already been registered but is pending approval by the account administrator.
The response.responseReasonText is null, in debugger on mouse over I see <Invalid CFStringRef>.
Workaround: get data from response.anetApiResponse.messages.messageArray.code/text/description
It is actually expected that the responseReasonText would be null in this situation. This field normally contains the results of an attempt to process a transaction. In this situation, no transaction has been attempted and it is necessary to look at the API response message.