Didn’t have any issues with our Ohme + Bluelink app (Ioniq 6) – but i haven’t tried the Hyundai app, refuse to use it due to bugs (showing range in km etc).
That said: while you wait for them to get back to you, you can still charge the car. In the Ohme app, set a schedule to charge only from 11:30pm to 5:30am, departure time like 10am next day (you have to set a departure time).
It will not take advantage of the “intelligent” part of Intelligent Go, but you still get discounted charging. Just slightly less convenient. Allows you to use the car proper at least.
edit: though, if the VW app is anything to go by, server issues are common – may be some issue Hyundai-side.
Prior: SEAT Ateca Xcellence Lux 1.5 TSI DSG MY19, VW Golf GTE PHEV DSG MY23
Current: Hyundai Ioniq 6 Ultimate
Next: we'll see what's available in 2028.