Since the Sequoia upgrade, I cannot make or receive Facetime calls on my iMac. Every time, I get a "Call Failed" message. This happens whether or not I initiate the Facetime video on my iMac or try to switch to the iMac from a call initiated on my iPhone.
iMac 27″, macOS 15.0
This is what happened to me, too. I had to turn off Voice Control (System Settings -> Accessibility -> Motor section). After that FaceTime started to work again. My MacBook Air M4 runs on MacOS Sequoia v. 15.4.1. Interestingly, Voice Control has caused me trouble earlier, too. The Copilot microphone did not turn on if Voice Control was enabled. It seems to me that this Accessibility program (Voice Control) has not been thoroughly tested and affects certain registers.
Thanks - This worked! I gave up on Apple Support too because after a 24+h migration, I was told to wipe the new laptop and see if the FT error was a HW issue. You saved me so much time!
Facetime not working since Sequoia 15.0.1 upgrade
