Mobile Battle.net: Line's Full (Several Days, Ongoing)

I first noticed this last weekend. When I try to login to battle.net via my phone it pauses on “Still Connecting” and then goes to "Line’s Full: “We’re currently experiencing an unusually high amount of traffic. We’ll get you in when we can, so please try again later!”

This error is constant and ongoing. I’ve tried updating battle.net to latest version (1.18.1). I’ve tried re-installing battle.net. I’ve connected via cellular and via wifi. I’ve turned airplane mode on and off (thinking that would clear DNS). I’ve restarted phone. None of these have made any changes. I still get the same Line’s Full error.

I am on iOS 15.5. I have no issues with battle.net on PC: that version works fine.