Was having some problems adding my Golf GTE to and found out that the Android 9 hotspot doesn't allow the car to communicate via WLAN for registration. Opened a customer care ticket and eventually got it resolved. As a final notice they sent me this:
Thought I'd let you all know in case you have any problems doing remote functions.We are glad to know that you are now able to use the Car-Net services.
However, we would like to kindly inform you, that from 10.06.2019 till 14.06.2019 maintenance work is planned on the IT system.
Intermittent service downtimes may be expected during maintenance work. The reason for this maintenance work is a major deployment of new features.