Screen sharing bug
QSince updating to macOS Sierra 10.12.4, I’ve had problems accessing my Mac using screen sharing and VNC from my iPad. Using another Mac is fine, but authenticating using the iPad’s on-screen keyboard fails. Using a Bluetooth keyboard with the iPad works fine. What’s wrong?
AThis is a bizarre bug which appears confined to Sierra 10.12.4, and results in the on-screen ß key not working on the iPad. If you enter any password containing capitals, Apple’s VNC server, to which it is trying to connect, sees only lower case letters, and refuses.
As you’ve discovered, you can work around it by not using an iOS on-screen keyboard; a Bluetooth keyboard or a Mac will do nicely, though. You could also change your password so that it doesn’t use capital letters.
It’s independent of the client app which you use in iOS, and appears to occur somewhere between 10.12.4 and Apple’s VNC Server. If you substitute another VNC server, such as RealVNC’s, then the on-screen keyboard works normally again. Full details are at bit.ly/realvnc_support_shift.