The Iphone BT App Link is not working

I checked with our developer and it will be very expensive to update our app to get it back into the Apple store, but there IS a workaround, since the app is truly just the mobile version of the website. You can either use your phone's browser to navigate to BeginnerTriathlete.com, and you'll see the exact same experience, OR you can use your phone's browser to navigate to BeginnerTriathlete.com and then create a "desktop icon" for your phone so you can click the icon and reach the mobile version (same as the app) using the icon like normal.

In Chrome, you click Share and choose "Add to Home Screen"
in Safari, you click Share and choose "Add to Home Screen" or use these instructions.

Is this site still active?

Yes, but it's getting very difficult to keep it so. We don't have nearly as many paid users, so it's not breaking even anymore.
If everyone who uses it regularly would sign up for a Bronze plan just to keep the lights on, it would be very helpful in keeping it going. There are ongoing hosting and software costs which have been reduced to a minimum, but I'm donating my time now, where I used to take a small salary from BT.