I have been using Zwift with windows 10 with my built-in bluetooth in a new laptop and since this morning the bluetooth is not working, but only in Zwift, I can connect everything.
I have tried Zwift Companion but there are lags with my pedals sometimes.
What have you done?
There was no Zwift update this week. 
Can you go into your windows Bluetooth settings and unpair everything. Then Try again.
I have restored Windows, the whole SO, I can´t use the built-in bluetooth. There is an ! in the bluetooth icon.
That can be a driver issue. Time to Google the problem with Bluetooth.
I have reinstalled the drivers, the point is that bluetooth is working perfectly with everything but Zwift.
I have just installed Rouvy and there´s no problem connecting my devices with the bluetooth.
After installing Rouvy, I have used Zwift again and it´s working now!!!
Hi Francisco
kind of same probleme here
how installing another bike software can solve your zwift problem ? can we count on magic ? 
I really don’t know the reason, I’m sure it is something of the SO. Bluetooth is working great now. I spent two days getting crazy with this Bluetooth problem.