Are you using the same email address in both cases (Sync and SUMO account) ?

In case of issues try to log in to the Firefox Account via this website.

• https://accounts.firefox.com/signin
• https://accounts.firefox.com/settings

Many thanks, cor-el. I guess the problem was that I'd used two different email addresses--and using an alternative link that you provided solved.

May I ask a further question? My "recovery key" seems to consist of 8 4-character strings separated by spaces. Is that correct? Or is the key perhaps any one the those 8 strings?

The Sync recovery key is one long 32-character string that is split into eight 4-character parts to make it easier to enter this code, so you need the full code.

cor-el said

one long 32-character string

Does that mean that the spaces are not part of the code?

Just type or paste the text as is displayed. I would expect the Firefox will remove all white space when processing the key code you entered. If it doesn't work then you can still try without the spaces. Note that a password reset will likely invalidate the code if you do not use the code instead of proceeding with the recovery key.

cor-el said

Note that a password reset will likely invalidate the code if you do not use the code instead of proceeding with the recovery key.

Don't understand. Could you perhaps rephrase?

If you change the password of the Sync Account then it won't be possible to decrypt data that was stored on the Sync server, so a password change action will cause all data to get wiped. After a password change you need to generate a new recovery key. You use the recovery key to access the Sync account data instead of doing a password change that will remove this data. Normally the Sync key is derived from the password and if you forgot the password then you can use the recovery key instead.

• https://support.mozilla.org/en-US/kb/reset-your-firefox-account-password-recovery-keys
• https://www.ghacks.net/2018/09/27/how-to-create-firefox-account-recovery-keys/