Firefox stores the credentials to login to the Sync account automatically in the logins.json file along with the other logins you possibly can save. This chrome://FirefoxAccounts entry with its password data in JSON format (kA and kB) is hidden from the Password Manager (about:logins). Are you possibly using ways to prevent Firefox from storing and keeping this JSON data in logins.json ?

Thanks for response, cor-el. I did not even know about existence of that file.

In case of issues, try to login to the Firefox Account via this website.

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

Thanks again, cor-el. I always login there. Still I have the same problem( please, see the attached picture).

As a test, can you download a different version of Firefox (Beta, Dev, or Nightly) and try to sync it?

The same story it is. It gets me disconnected instantly. Thanks for suggestion though.

Is there anything useful in the Browser Console ?

• https://firefox-source-docs.mozilla.org/devtools-user/browser_console/

I do know what is useful, cor-el.

As you can see, the screenshot shows that there are errors with Sync and advise you to check Sync logs.

You can open about:sync-log via the location bar to see if recent Sync logs are available. You can upload the file to a website like Pastesite if you can't post the content of the file in a reply.

• https://pastesite.org/

Here is the content: 1680749340776 FirefoxAccounts DEBUG FxAccountsPushService unsubscribed 1680749340777 Sync.LogManager DEBUG Done deleting files. 1680749340984 FirefoxAccounts DEBUG FxAccountsWebChannel message received: fxaccounts:fxa_status 1680749340984 FirefoxAccounts DEBUG fxa_status received 1680749340984 FirefoxAccounts DEBUG service: null 1680749340984 FirefoxAccounts DEBUG is private browsing: false 1680749377783 FirefoxAccounts DEBUG FxAccountsWebChannel message received: fxaccounts:fxa_status 1680749377783 FirefoxAccounts DEBUG fxa_status received 1680749377783 FirefoxAccounts DEBUG service: null 1680749377783 FirefoxAccounts DEBUG is private browsing: false 1680749412002 FirefoxAccounts DEBUG FxAccountsWebChannel message received: fxaccounts:fxa_status 1680749412002 FirefoxAccounts DEBUG fxa_status received 1680749412002 FirefoxAccounts DEBUG service: null 1680749412002 FirefoxAccounts DEBUG is private browsing: false 1680749632751 FirefoxAccounts DEBUG FxAccountsWebChannel message received: fxaccounts:fxa_status 1680749632751 FirefoxAccounts DEBUG fxa_status received 1680749632751 FirefoxAccounts DEBUG service: null 1680749632751 FirefoxAccounts DEBUG is private browsing: false 1680749756460 FirefoxAccounts DEBUG FxAccountsWebChannel message received: fxaccounts:fxa_status 1680749756460 FirefoxAccounts DEBUG fxa_status received 1680749756460 FirefoxAccounts DEBUG service: null 1680749756460 FirefoxAccounts DEBUG is private browsing: false 1680750303727 FirefoxAccounts DEBUG FxAccountsWebChannel message received: fxaccounts:fxa_status 1680750303727 FirefoxAccounts DEBUG fxa_status received 1680750303727 FirefoxAccounts DEBUG service: sync 1680750303727 FirefoxAccounts DEBUG is private browsing: false 1680750303804 FirefoxAccounts DEBUG FxAccountsWebChannel message received: fxaccounts:loaded 1680750303804 FirefoxAccounts WARN Unrecognized FxAccountsWebChannel command: fxaccounts:loaded 1680750308740 FirefoxAccounts DEBUG FxAccountsWebChannel message received: fxaccounts:can_link_account 1680750308740 FirefoxAccounts DEBUG FxAccountsWebChannel response: {"command":"fxaccounts:can_link_account","messageId":"16807503087402","data":{"ok":true}} 1680750309386 FirefoxAccounts DEBUG FxAccountsWebChannel message received: fxaccounts:login 1680750309386 FirefoxAccounts DEBUG Webchannel is logging a user in. 1680750309387 FirefoxAccounts DEBUG setSignedInUser - aborting any existing flows 1680750309387 FirefoxAccounts DEBUG removing account data 1680750309387 FirefoxAccounts TRACE starting write of json user data: null 1680750309409 FirefoxAccounts TRACE finished write of json user data - took: 22 1680750309410 FirefoxAccounts TRACE storage set finished clearing account data 1680750309410 FirefoxAccounts DEBUG account data reset 1680750309410 FirefoxAccounts TRACE StorageManager finalizing 1680750309410 FirefoxAccounts TRACE StorageManager finalized 1680750309410 FirefoxAccounts TRACE initializing new storage manager 1680750309410 FirefoxAccounts DEBUG writing plain storage: ["email","sessionToken","uid","verified"] 1680750309410 FirefoxAccounts TRACE starting write of json user data: ["email","sessionToken","uid","verified"] 1680750309430 FirefoxAccounts TRACE finished write of json user data - took: 20 1680750309430 FirefoxAccounts DEBUG writing secure storage: ["keyFetchToken","unwrapBKey"] 1680750309430 FirefoxAccounts TRACE starting write of user data to the login manager 1680750309432 FirefoxAccounts TRACE finished write of user data to the login manager 1680750309432 FirefoxAccounts TRACE initializing of new storage manager done 1680750309432 FirefoxAccounts DEBUG Notifying observers of fxaccounts:onlogin 1680750309432 Sync.SyncAuthManager DEBUG observed fxaccounts:onlogin 1680750309432 Sync.SyncAuthManager INFO Sync is not configured, so ignoring the notification 1680750309432 FirefoxAccounts DEBUG FxAccountsProfileClient: Initialized 1680750309432 FirefoxAccounts TRACE FxAccountsPush registerPushEndpoint 1680750309432 FirefoxAccounts DEBUG FxAccountsProfileClient: Requested profile 1680750309432 FirefoxAccounts DEBUG getOAuthToken enter 1680750309434 FirefoxAccounts INFO fetching updated device list 1680750309435 FirefoxAccounts INFO Already fetching device list, return existing promise 1680750309478 Services.Common.RESTRequest DEBUG GET request to https://api.accounts.firefox.com/v1/account/devices?filterIdleDevicesTimestamp=1678935909435 1680750309481 Services.Common.RESTRequest DEBUG POST request to https://api.accounts.firefox.com/v1/oauth/token 1680750309481 Services.Common.RESTRequest DEBUG POST Length: 81 1680750309598 FirefoxAccounts DEBUG FxAccountsPush got subscription 1680750309600 FirefoxAccounts INFO Generating and persisting encrypted sendtab keys 1680750309600 FirefoxAccounts INFO Could not find sendtab keys, generating them 1680750309604 FirefoxAccounts DEBUG _updateAccountData with items: ["device"] 1680750309604 FirefoxAccounts DEBUG writing plain storage: ["email","sessionToken","uid","verified","device"] 1680750309605 FirefoxAccounts TRACE starting write of json user data: ["email","sessionToken","uid","verified","device"] 1680750309606 FirefoxAccounts TRACE finished write of json user data - took: 1 1680750309606 FirefoxAccounts DEBUG writing secure storage: ["keyFetchToken","unwrapBKey"] 1680750309606 FirefoxAccounts TRACE starting write of user data to the login manager 1680750309613 FirefoxAccounts TRACE finished write of user data to the login manager 1680750309613 Services.Common.RESTRequest DEBUG POST request to https://api.accounts.firefox.com/v1/account/scoped-key-data 1680750309613 Services.Common.RESTRequest DEBUG POST Length: 84 1680750309891 Services.Common.RESTRequest DEBUG GET https://api.accounts.firefox.com/v1/account/devices?filterIdleDevicesTimestamp=1678935909435 200 1680750309891 Hawk DEBUG (Response) /account/devices?filterIdleDevicesTimestamp=1678935909435: code: 200 - Status text: OK 1680750309892 Hawk DEBUG Clock offset vs https://api.accounts.firefox.com/v1: -892 1680750309892 FirefoxAccounts INFO Got new device list: 1680750309892 FirefoxAccounts TRACE Our push subscription looks OK 1680750309893 FirefoxAccounts INFO updating the cache 1680750309977 Services.Common.RESTRequest DEBUG POST https://api.accounts.firefox.com/v1/oauth/token 200 1680750309977 Hawk DEBUG (Response) /oauth/token: code: 200 - Status text: OK 1680750309977 Hawk DEBUG Clock offset vs https://api.accounts.firefox.com/v1: -977 1680750309977 FirefoxAccounts DEBUG _updateAccountData with items: ["oauthTokens"] 1680750309977 FirefoxAccounts DEBUG writing plain storage: ["email","sessionToken","uid","verified","device","oauthTokens"] 1680750309977 FirefoxAccounts TRACE starting write of json user data: ["email","sessionToken","uid","verified","device","oauthTokens"] 1680750309978 Services.Common.RESTRequest DEBUG GET request to https://profile.accounts.firefox.com/v1/profile 1680750309979 FirefoxAccounts TRACE finished write of json user data - took: 2 1680750309979 FirefoxAccounts DEBUG writing secure storage: ["keyFetchToken","unwrapBKey"] 1680750309979 FirefoxAccounts TRACE starting write of user data to the login manager 1680750309985 FirefoxAccounts TRACE finished write of user data to the login manager 1680750310011 Services.Common.RESTRequest DEBUG POST https://api.accounts.firefox.com/v1/account/scoped-key-data 200 1680750310011 Hawk DEBUG (Response) /account/scoped-key-data: code: 200 - Status text: OK 1680750310011 Hawk DEBUG Clock offset vs https://api.accounts.firefox.com/v1: -1011 1680750310011 FirefoxAccounts DEBUG Fetching keys with token true from https://api.accounts.firefox.com/v1 1680750310012 Services.Common.RESTRequest DEBUG GET request to https://api.accounts.firefox.com/v1/account/keys 1680750310172 Services.Common.RESTRequest DEBUG GET https://api.accounts.firefox.com/v1/account/keys 200 1680750310172 Hawk DEBUG (Response) /account/keys: code: 200 - Status text: OK 1680750310172 Hawk DEBUG Clock offset vs https://api.accounts.firefox.com/v1: -1172 1680750310173 FirefoxAccounts DEBUG Keys Obtained: https://identity.mozilla.com/apps/oldsync, sync:addon_storage 1680750310174 FirefoxAccounts DEBUG _updateAccountData with items: ["scopedKeys","kSync","kXCS","kExtSync","kExtKbHash","keyFetchToken","unwrapBKey"] 1680750310174 FirefoxAccounts DEBUG writing plain storage: ["email","sessionToken","uid","verified","device","oauthTokens"] 1680750310174 FirefoxAccounts TRACE starting write of json user data: ["email","sessionToken","uid","verified","device","oauthTokens"] 1680750310174 Sync.BulkKeyBundle INFO BulkKeyBundle being created for undefined 1680750310174 FirefoxAccounts DEBUG _updateAccountData with items: ["encryptedSendTabKeys"] 1680750310174 FirefoxAccounts INFO registering with available commands: ["https://identity.mozilla.com/cmd/open-uri"] 1680750310174 FirefoxAccounts DEBUG registering new device details 1680750310175 FirefoxAccounts TRACE finished write of json user data - took: 1 1680750310175 FirefoxAccounts DEBUG writing secure storage: ["scopedKeys","kSync","kXCS","kExtSync","kExtKbHash"] 1680750310175 FirefoxAccounts TRACE starting write of user data to the login manager 1680750310180 FirefoxAccounts TRACE finished write of user data to the login manager 1680750310180 FirefoxAccounts DEBUG writing plain storage: ["email","sessionToken","uid","verified","device","oauthTokens","encryptedSendTabKeys"] 1680750310180 FirefoxAccounts TRACE starting write of json user data: ["email","sessionToken","uid","verified","device","oauthTokens","encryptedSendTabKeys"] 1680750310181 Services.Common.RESTRequest DEBUG POST request to https://api.accounts.firefox.com/v1/account/device 1680750310181 Services.Common.RESTRequest DEBUG POST Length: 859