Delete the signedInUser.json file in the Firefox profile folder and delete the Weave folder (Sync was formerly named Weave).

Remove an existing chrome://FirefoxAccounts entry in the Firefox Password Manager.

If that isn't enough then delete the prefs.js files to reset all prefs and maybe also delete the compatibility.ini file to reinitialize the profile.

You can use this button to go to the current Firefox profile folder:

• Help > Troubleshooting Information > Profile Directory:
  Windows: Show Folder; Linux: Open Directory; Mac: Show in Finder
• http://kb.mozillazine.org/Profile_folder_-_Firefox

Note that changing the Sync password will wipe all data stored on the Sync server.

Can you log in to the Sync account via this page?

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

Thank you for your answer.

Delete the signedInUser.json file in the Firefox profile folder and delete the Weave folder (Sync was formerly named Weave). Remove an existing chrome://FirefoxAccounts entry in the Firefox Password Manager. If that isn't enough then delete the prefs.js files to reset all prefs and maybe also delete the compatibility.ini file to reinitialize the profile.

I tried everything you have written, but nothing has solved my problem.

Can you log in to the Sync account via this page?

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

Yes, I can log in on the account page.

Create a new profile to test if your current profile is causing the problem.

See "Creating a profile":

• https://support.mozilla.org/kb/profile-manager-create-and-remove-firefox-profiles
• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Profile_issues

If the new profile works then you can transfer files from a previously used profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over problems.

• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

It doesn't work with a new profile, here is the latest log : http://pastebin.com/jWhyt1hB

It looks like Firefox tries to connect to

• https://sync-241-us-west-2.sync.services.mozilla.com/

but it's not reponding while both

• https://sync-240-us-west-2.sync.services.mozilla.com/
• https://sync-242-us-west-2.sync.services.mozilla.com/

are responding.

Hello,

I finally created a new account, it works with it. So I'll use this new account and delete the old one.

FYI : I think that my problem was with the server, because my new account is connected on https://sync-331-us-west-2.sync.services.mozilla.com/ and works perfectly.

Thanks for your help.