If you are ever having problems with the ParkMobile app, you can easily make payments on the ParkMobile website. Visit ParkMobile.io and either select "Enter Zone Number" or "Sign In/Sign Up" then select "Zone Parking". This will take you to a sign in page where you can enter your ParkMobile username and password. In this web interface, you will be able to select your license plate and enter the zone number to start your parking session. You can see more details in the images below. If you have problems you can submit a support ticket.