iCloud login via Ubuntu and Firefox does not work

In Firefox, open about:config address and add the parameter general.useragent.override to override the userAgent string. To get the right value,

1. Open the console (F12)
2. Type navigator.userAgent
3. Copy/Paste the returned value into general.useragent.override parameter, then remove " Ubuntu;"

It's October 2025, and I just installed Ubuntu 24.04.3 LTS with the Firefox Snap pre-installed. I could not find any of the settings mentioned in this thread - and after looking around in about:config with keyword 'firefox', I changed the setting: general.useragent.compatMode.firefox from 'false' to true.

Firefox: 143.0.4 (64-bit)

Mozilla Firefox Snap for Ubuntu

Canonical-002-1.0

Thanks for the thread

Nevermind, I fixed the issue by removing the icloud.com cache from the browser, then I was able to login fine.

Changing the user-agent to something else than Firefox works, corresponding question in Firefox support https://support.mozilla.org/fr/questions/1529931

It seems Firefox is blocked on-purpose based on user-agent at Apple side.

Confirming having the same problem for a few days now. I use the latest version of Firefox on Kubuntu 24.04.3 LTS and can't login to icloud.com and account.apple.com.

I installed Brave just to access my iCloud environment and that works.

I’m also having the same issue. When logging into the icloud.com website, I get the error “Identity could not be confirmed”, using Firefox 142 and 128 ESR.

However, I’m able to log in to any site when using “Sign in with your Apple account”.

I tried accessing through Edge and Brave on Ubuntu 22.04.5, and the login worked normally.

Using Firefox on Fedora, the login also worked.

I tried changing the user agent in Firefox, but it didn’t help.

Same problem here with xubuntu and Firefox.

Tried on windows and Linux mint with Firefox browser and there it works.

Currently, I use Google Chrome on xubuntu For the iCloud and With that it works fine

Clearing the cache didn't work. Changing the user-agent did the magic, and it worked. The problem is only with the login. Once you are logged in, there is no issue.

I just want to add that, while I cannot login to icloud.com using Firefox, I *can* login here to Communities using Firefox and my Apple ID. So, there's some inconsistency in the webapps running icloud.com and Communities.

FWIW, I can login to icloud.com using the Brave browser.

p.s. I realize that there is a work-around, but I am adverse to installing a Firefox extension in order to do that.

Exact same issue here, also resolved by spoofing my user agent to literally anything else. That does pretty much confirm that apple is either intentionally or accidentally blocking the specific combination of user agent - Ubuntu/Firefox. I left feedback, I hope they will resolve this soon...

I have the same issue with Firefox in Ubuntu installed on a Mac. Works from Chromium.

I have the identical problem on Windows with firefox. Login with correct password or passkey always fails on icloud! But I can login to this website which is apple.com without problem.

Please tell me how to login to icloud, or the work around.

As suggested here, I changed my User Agent using [User-Agent Switcher and Manager] and for me, it actually breaks icloud.com entirely:

[Edited by Moderator]