What is the url for the iOS app as I cannot seem to connect, the default url for logging in does not seem to work.

There is no official iOS app. There is a third party one https://www.zenphoto.org/news/zenphoto-ios-app/ with a related plugin. I have no idea if that is still maintained and working.

Thank you, I couldn't see what url to point to, and everything I have tried doesn't seem to work. I will try and contact the dev.