I bought a TS408 and registered it this week, it couldn't do what I need it to so I purchased a TS601 after talking to a Autel rep who said it should. I just received it today and wanted to register and update it, after plugging it in to the computer it asked if it could change the ID and I clicked yes, after that the unit stopped working and said vehicle authoriztion not allowed, obtain vehicle authorization and shows OK in the bottom left. no button I push is accepted, and it wont let me register it online as well, needless to say I am not very happy at this point after spending a total of about $500 for the 2 devices of which one is inadequate and the other is not working.
Just a shot in the dark. Yesterday I got the 601 and wanted to update it which meant getting a log in etc. This is my first device. When it came to registering the new unit, it asked for SN and password. I thought it meant the password I used to log in on the site. Seems the password they want is specific to each device. It's not the one to log into the site, it listed in (if I remember right) the about section on the device itself where you can also see the serial number. It took me a little bit to figure that out.
Since you have a device already you may know this but I thought I'd throw that out there.