User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:68.0) Gecko/20100101 Firefox/68.0

Steps to reproduce:

i tried to open an icloud link, i made from the iphone to myself.

Actual results:

when trying to open the link (tried several times with different links and on different windows devices) a connection error appears (verbindingsfout) .

Cannot connect to server.

After clicking OK it keeps trying to reconnect, with a result that it ends in a loop, giving the same error

Expected results:

The link should have opened properly, loading all the attachments.

I did not manage to reproduce your issue on my system.
I used this link: https://share.icloud.com/photos/0GzH58spUxes4-4I54Bez5OkQ

Please help us with some information:

1. Can you reproduce with this link?
2. Can you share your link or information on how you created it?
3. If this issue still reproduces, I need to ask you to attempt reproducing it in safe mode. here is a link that can help you:
   https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode
   If it still reproduces in safe mode it means it might be a valid and serious bug.
4. Please also tell us if you see any errors in the browser console. (Open the browser console <CTRL+SHIFT+J> before reproducing the issue and check whether any errors were displayed while performing the steps to reproduce. Please copy the errors to this bug.

Thank you for your contribution!

The problem persists with every icloud link, and even with https://www.icloud.com/

By just visiting the website I receive the error.

So I understand that you CAN reproduce with my link.
What about in safe mode?
Does the Browser console show any errors?
Thanks.

I can confirm this issue with Firefox 74 running on Linux. I can trigger it at will by enabling the "privacy.resistFingerprinting" config flag. Disabling it restores icloud access.

I succeeded in reproducing this issue on all the last versions of the main channels, on Windows 10 and Ubuntu 18. I think the console warning that appears at the same time the pop-up error does is the "Could not authenticate - TIMEOUT" warning.

Steps used:

1. Open browser.
2. Go o about:config
3. Set the value of the "privacy.resistFingerprinting" to true.
4. Restart session.
5. Load: www.icloud.com and wait.
   Actual: "Connection ERROR - iCloud encountered an error while trying to connect to the server." error pop-up is displayed.
   Expected: The website load as expected and the error is not shown.

I can confirm this for FF77 on macOS as well.

If "privacy.resistFingerprinting" is set to true, Apple ID login frames (eg the login link on https://music.apple.com) will fail to load.

If "privacy.resistFingerprinting" is set to false, the login form will load as expected.

This is not a networking bug.

Tom, can you block this on the right bugs, please? Thanks!

Login to icloud.com currently works for me on Firefox 109 with RFP enabled.