Some users may receive a Webservice Unavailable message when trying to NetFile an AT1 or CO-17 from the corporate T2 module.
The message following this error incorrectly indicates that the return can be transmitted to the CRA Transmission Web Site. CO-17 and AT1 do not use the CRA Transmission Web Site, but their own provincial government agencies - Quebec and Alberta respectively.
This message will be updated in a future release to not only include the specific provincial agency message.
However, in the event of this message appearing, follow the usual troubleshooting steps found in the article How to set up Internet Options if receiving error message when transmitting a return to the CRA.