Help:TRS19 MyTrainzLoginInterface
From TrainzOnline
Build Authorisation Failed
A MyTrainz account is required for access to certain Trainz products and features.
If you are attempting to log in to a Trainz product with a valid MyTrainz account, but authorisation fails, then the account you are using does not have the appropriate access.
The most likely cause for this issue is due to using a different account to the one that was used to purchase the product.
If you are using the correct account and access is still denied, or if you are unable to resolve the issue, then please contact Trainz Helpdesk
Please include your order details and details of any accounts used to purchase or register previous versions of Trainz.