Can't log into iCloud on the browser (Chrome or Safari)
I'm unable to log into iCloud on an internet browser.
Submitting my email address and password results in two factor authentication code being generated, and the code appears as expected on my iPhone.
Having entered the authentication code, I am then asked to verify my Apple ID email address or enter a new one. Whether I enter my mac.com address or an alternative address, I am unable to progress further, and only get "An unknown error has occurred" alert.
MacBook Air 13″, macOS 11.7