Adobe services and products cannot be used in Cuba, Iran, North Korea, Syria, Crimea, or the so-called Donetsk and Luhansk People’s Republics. Firefly is also not available in Russia, Belarus, and China.
Firefly is best accessed via a desktop browser, and is not currently supported on tablets or mobile devices.
Firefly supports Chrome, Safari, and Edge browsers. (Brave browser also works for me.)
Do a hard refresh on your browser, Ctrl(Cmd) + Shift + R. If this doesn't work, try accessing the site with an incognito browser. Note, favorites won't be saved when doing so.