Hello,
GH3000 can be updated only with configurator. It cannot be updated via FOTA/FOTA WEB.
You can get the configurator for your GH3000 from the following link (I can see that the website is currently down, but it should be up and working shortly):
Link: http://teltonika.lt/client/
User: GH3000
Password: RGO479HLL
Archive password: 1234
Regards,