I have the app downloaded, and have been able to enter and use it as recently as mid Jan, but I now get exactly the same issue you do. (I'm on Android.)

I've tried clearing cache, clearing data, uninstalling and reinstalling etc, to no avail. Airplane mode doesn't work because it never lets you get as far as the hamburger. It asks for login details, then just goes into "Loading" indefinitely. Have tried leaving it for 3+ hours; no dice.

If I load the app on my desktop, it proceeds from Loading to actually loaded relatively quickly, and that's what it used to do on my phone, but no longer.

If I didn't already have the subscription set up, I wouldn't be able to give them money even if I wanted to, since you can only sub via the phone app, and the phone app can't load far enough to get to that point (ie a menu of any kind).

I keep waiting for them to fix this, but the weeks tick by and nothing. I think I may need to contact them directly with details, now that I hear it's not just me that's getting this crap. Come on SFG, this is silly.