Sorry to hear that didn't work. It sounds like it's the same setting, but maybe a different route to get to it. Below are some photos of what I do as well as the steps:
Go to main menu (Home icon)
Scroll across to "Connection settings" and click.
I'm presented with four options: "Mobile network, Bluetooth, Wi-Fi, data plans"
I selected "Mobile network".
I'm presented with four lines, the first of which is: "Switch on car phone/data module" (enabled for me so I just click it off, wait and click it back on).
I noticed underneath that there's "Automatic network section" but it's on and greyed out. There's a sub-item showing it's using "Audi connect" as the network provider.
I wonder if there's an issue with the network provider that the SIM card is connecting to. Not so much a hardware issue in the car or software issue with the app, but an issue with Audi's own "mobile network". I'm not in the US, but I did hear recently that some mobile networks in your part of the world are turning off their 3G capability and this has affected BMW i3s from a few years back that can't connect over 4G. Audi connect network probably sits on top of a mainstream provider like Verizon, T-Mobile or AT&T.
Have you tried Audi's social media people?
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