Website address unvalid in Matomo Mobile 2 app

Hi, we have been using the Matomo Mobile 2 app to monitor our website. It has been working find until a couple of days ago when I tried to log in and it said the url was invalid. I tried deleting the account off the app and logging in again, however it is still giving me the same error.

The website is working fine online so I don’t know why the app would suddenly not connecting. If you could give any solutions to this, that would be great.