GoTo Mobile App: Delayed Ringing or Doesn't Ring At All

We primarily utilize Yealink phones in our GoTo Connect setup, but we've encouraged our users to also use the GoTo Mobile app for answering calls to their lines when away from their desks or working remotely.

There is a problem however where calls will not consistently show up as ringing in the GoTo Mobile App on cell phones. There is often a delay, and sometimes that delay is so long that the GoTo Mobile App doesn't ring at all and the call is missed.

There is no delay on the desk phone, and there is no delay on the GoTo Desktop app, it's just the mobile app that operates inconsistently and often has a variable delay before it rings to the point where it might not ring at all because the delay was too long. It seems to be worse on some peoples' phones than others. Uninstalling and reinstalling the mobile app doesn't seem to have any effect.

What's going on here? What can be done about this? At the moment, we can't really rely on the mobile app for answering calls which poses some serious issues for us since we've set up systems that rely on the ability to answer calls via the mobile app.