Google’s Pixel 4 smartphones have run into another face unlock-related issue. This time, the feature is not working at all for some Pixel 4 and 4 XL users. Re-enrolling faces or resetting the phones fails to solve the problem, Android Police reports, compiling user complaints from several online forums. To recall, Pixel 4 had a pre-launch issue of eyes not needing to be open for face unlock.

The latest issue apparently started surfacing back in November but picked up the pace recently. Interestingly, the December 2019 security update triggered the issue for some users, though it’s also occurring without any apparent triggering action for others.

Affected users are seeing error messages reading “Can’t verify face. Hardware not available” or “Can’t verify face. Try again.” Oddly, many of those users were prompted to re-enroll their face before the issue emerged, despite everything working fine.