Long delay / crash on initial login

When a Matrix user signs in to the app for the first time using their pre-existing account (that is, an account that they did not create using this app), the app seems to lock up. It waits for a long time, but never logs the user in. Sometimes this results in a crash.

Device: Android Emulator (Pixel 4) -- also I think this happened on my real Moto G Play (2021)