App can be a bit hit and miss and likes to tell you that your pride and joy is unlocked when it isn't or that it's windows are open when they're not but for heating and clearing windscreen it works fine!!
I'm also struggling with this damn Cupra Connect App, especially in colder mornings.
I'm stopping the charge before it reaches 100%, so I can charge the last few percent the next morning before departure. The car is parked overnight quite far from me, and connected to a charger that switches off automatically after 4h since the start of the charging session. This means I cannot use the "departure time" setting on the car (or App), since the charger might be switched off when the car would like to start charging before departure.
However, what I try to do is to manually start the charging station from it's own App, and after that I have to tell Cupra to start charging. In
most cases the Cupra App will reply "Sorry, something has gone wrong", in some cases it will tell me that the car is "Not connected / unplugged", and in less than 10% of the cases (maybe 5%) it will start charging.
However, every time I get one of the above errors, I'm able to start the pre-heating of the car - which will drain the battery, of course - since the car has no idea it's connected to the charging station, or when it knows it's connected, it doesn't know that the station is "alive".
So indeed, in most cases the remote heating works just fine, but the charging request fails most of the time...