X-Frame-Options Policy since Firefox update

[jsrolon]

Hi! I'm currently using Firefox 77.0.1 (64-bit). I had been using the extension successfully on beeminder.com for some weeks, but since around last week I've been getting this X-Frame-Options error.

Anything I can do to fix this? Thanks!

EDIT: I'm experiencing this both in macOS High Sierra 10.13.6 and on Windows 10.

[kostyfisik]

I have the same issue after Firefox upgrade (along with upgrade to fresh Ubuntu). Does the author @excitedleigh can reproduce this?