Syncing Issue with Bitwarden Firefox Add-on: "Syncing Failed" Error


I’m encountering a persistent syncing issue with the Bitwarden add-on in Firefox and would greatly appreciate any insights or suggestions from the community.

Issue Description:
When I try to manually sync the Bitwarden add-on in Firefox (Settings>Sync>Sync Vault Now), it fails and displays a “Syncing failed” error message.
Interestingly, if I create a test item in the Firefox add-on, it successfully syncs to my phone, indicating some level of sync functionality.
However, there is at least one item on my phone that isn’t appearing in the Firefox add-on.
Manually initiating a sync results in failure, but other actions do produce output in the debugging console, suggesting that debugging is working correctly.
As of my last check, both Firefox and the Bitwarden add-on are up to date, and Bitwarden’s service status ( shows all systems operational.

Troubleshooting Steps Taken:

Verified that both Firefox and the Bitwarden add-on are updated to the latest versions.
Checked my internet connection, which is stable.
Restarted Firefox.
Inspected the Firefox Console Logs (via about:debugging) but found no relevant output when the sync issue occurs.

Additional Information:

Firefox version: 120.01 (64bit)
Bitwarden add-on version: [Your Bitwarden add-on version]
Operating System: 6.6.7-arch1-1
Other browsers/devices where sync is working: iOS 17.1.2

Any idea what might be causing this issue or any additional troubleshooting steps I could try? If there’s more information I can provide to assist in diagnosing this problem, please let me know.

Thank you!

(edit: formatting)
edit 2: Manually logging out then back in has allowed the add on to sync. Bit embarrassed I didn’t think to try that though I think there is probably an issue that needs to be resolved here and I’d be happy to provide more info -though I’d need to know what info would be useful). Of note to anyone reading: restarting my browser forces reentering master passwd but that is NOT the same as logging out then back in.

edit 3: submitted a bug report, hope it’s useful Syncing Issue with Bitwarden Add-on in Firefox · Issue #7243 · bitwarden/clients · GitHub


Same issue, cannot sync inbound items to FF on my Mac

FF 120.0.1 (64-bit)
BW 2023.12.0
MacOS 14.1.2
Other devices: working on Android 14, Windows 11 Firefox

Adding to this that i’m experiencing the same issue. Firefox BW addon fails to sync but mobile syncs fine still.

Inspecting the pop-out addon window for console & network errors shows no logs. The status page at the time of my reply still shows all systems operational.

Desktop: Windows 11
Mobile: iPhone iOS 17.2
FireFox: 120.0.1
BW Extension: 2023.12.0

I came on to research as I had the same issue with my selfhosted instance. Advice dotted around other threads over the last cople of days was to log out of Bitwarden and back in. This fixed it for me both on Windows desktop and Firefox add on.

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I initially did try logging out and back in between closing Firefox and the same issue occurred.

I did just make a change to my account and now the syncing works again though.

I went here: Bitwarden Web Vault
and increased my KDF iterations as mine were way below the recommended value. Applying that change made my extension session expired and when I logged back in, the sync works once again.


I have some concerns about logging out and in. If my clients can’t sync, won’t that result in loss of entries? I could now have entries that cannot be synced because of these mysterious “Syncing failed” errors. This tells me that however long this has been going on, my new passwords are not saved in my online vault since then. And the Firefox extension didn’t even warn me about that for days syncing now didn’t work. It also can’t show my passwords sorted by date added, so I have no idea if I have passwords added since the extension is detached or not, or which passwords are they.

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I’ve also been having this issue. Your mileage may vary, but I was able to change the KDF as recommended by ddax, which killed all my sessions, then log back in. I confirmed that a password added in the extension after syncing failed made its way onto my other devices after changing the KDF fixed sync’ing.

Created an account to just chime in. I also was having syncing issues on one of my PCs I reset the KDF as well and it fixed it.

Same happened to me, and i figured out whats was happening:
It was only happening with my laptop while i was at home. This is because router is not able to resolve you dns name (a.k.a from inside you local network… unless you can enable the NAT Reflection/Loopback in your router. Unfortunatelly my router cannot do that, and and was not able to configure an internal. I found 2 solutions… any of them elegant:

  1. Configure in my computer in the hosts file (C:\windows\system32\drives\etc\hosts) this:
    Unfortunatelly doing this causes the opposite effect… bitwarden will only work while im at
    home inside my local network (or with VPN activated)
  2. Whenever i need to synchronize my bitwarden vault, i just connect my laptop to my mobile phone shared wifi… so i access from outside my local network.

I think that it could be possible to configure a DNS inside my local network, so that this could work both from inside and outside… but didn´t have time to investigate about this.

I hope this helps at least to workaround the issue.

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Created an account just to say this (logout → login) worked for me. Thanks!

Happy to confirm manually logging out and back in worked for me too. (It’s under the Settings tab > Account heading > Log Out)

Thank you!


same issue and it worked logging out and in again

Same Issue Here. Firefox Browser Extension Sync fails.
MacOS version 14.3 Beta (23D5043d)
Firefox version 121.0.1 (64-bit)
Bitwarden Firefox Extension version 2023.12.1
Bitwarden MacOS App version 2023.12.1 (16254)

Same here. Sync failed

Microsoft Windows [Version 10.0.19045.3803]
Firefox 121.0 (64-bit)
Bitwarden Firefox Extension version 2023.12.1

I did encounter an error that said something like “Your encryption method is too old” or something but I’m unable to reproduce it.

Explicitly logging out in the Firefox Extension and logging in again SOLVED this issue though.

I have the same problem. My vault says it hasn’t synced since 12/20/23 but a login I created 1/7/24 is there on FF for Windows. I have disabled ad blocker, logged out and logged back in multiple times, rebooted multiple times and I cannot get it to sync. I only discovered I wasn’t synced because my Chromebook, which says it was synced on 1/6/24 does not have the new login. I cannot get either device to sync. I have reset the clock on Windows but I can’t do that on Chromebook. Neither device will sync.

FF 121.0.1
Bitwarden 2023.12.1

Chrome OS 119.0.6045.214
Bitwarden 2023.12.1

Update: rebooted router and repeated steps above, now working.

I have had this issue. When I signed-in to the site, it directed me to increase the KDF iterations under Encryption Key Settings. Once doing this, sync worked. Then again, it did cause me to logout and login again, which might have corrected the issue. If you’re still having issues after logging out and in again, check your KDF iterations.