Apologies just realised answering another post it's not the LTE it's the GPS/GNSS antenna (got the two mirrors mixed up) but still the likely cause of the error as the SOS system can't determine your position.
Antennas on a 6.1 in my post here:
Hi, A while ago I knocked of my drivers side wing mirror on my t6.1. I replaced it with an aftermarket from eBay but it vibrates when driving making it hard to use. Looking for a used t6.1 drivers side wing mirror seems like a non starter but there are quite a few t6 wing mirrors available...
www.t6forum.com