I had it usually crash when I was trying to get it to turn on the heat. Someone recommended that I make sure the doors are locked prior to trying to turn the heat on and use the website
https://owners.kia.com/content/owners/en/kia-owner-portal.html/
I found the website MUCH faster and is working so far, but haven't used it enough to say whether that will always work. I do know that the mobile app continues to be slow as molasses and rarely work for the climate control. The last time I tried the mobile app to turn on the heat, it failed like usual. The doors were definitely lock prior to logging in, but I was several miles away on a shuttle bus. Don't know if being farther away or in a moving vehicle would be a problem. I usually can lock the doors with the mobile app if I forget, but I have only been in the store or office when trying, so still pretty close to the car.