Thank you Straggler for the report. I wasn't able to repro with TD bill pay on Firefox 131 Release, with and without ETP-Strict. Could you please check the value of this pref: network.cookie.cookieBehavior.optInPartitioning in your about:config? This is 'false' by default in 131 Release so I'd like to confirm that consistency.

In your about:config, if `network.cookie.cookieBehavior.optInPartitioning` is false - which is the correct value you want, could you then please try flipping the pref `network.cookie.CHIPS.enabled` to false and then reload your bank page and see if this fixes your problem? Your repro and testing will be greatly appreciated for faster debugging and fixing as we don't have a repro. As always, we are grateful to have you as a Firefox user.

^: More about CHIPS (Cookies Having Independent Partitioned State).

• https://github.com/privacycg/CHIPS

Thank you for the help. Flipping the pref `network.cookie.CHIPS.enabled` to false immediately solved my problem and I was able to get into Billpay.

Thank you.

Thank you, this is of great help. Return information means a lot to the development team.

If anyhow possible, could you please test the page using Chrome? Since behavior is the same, we expect this to not work on Chrome as well.

Additionally, if you change network.cookie.CHIPS.enabled back to true and refresh the page - does the page break again? Thanks in advance.

Sorry, but I don't even have Chrome installed on my computer. If I get stuck somewhere I just fire up MS Edge and Billpay did work with that.

Regarding your 10:19 question, Reverting back does break the page again.

"Not Found

The requested URL was not found on this server."

Thank you.

With that pref being set to true, if you repeat the entire workflow - meaning, restart Firefox, log into the website and go to problematic tab (billpay) - is the error still 'not found' or are you redirected to 'You might have cookies blocked or cross-site tracking prevented.', the original error?

Doing as you asked, I get the original response"

"Why can't I access Bill Pay?

You might have cookies blocked or cross-site tracking prevented. Depending on what browser you're using, check your settings for these terms:

   Block third party cookies
   Cookie tracking
   Cross-site tracking

Make sure cookies are not blocked and cross-site tracking is enabled. Follow any additional instructions in your browser once you have adjusted these settings."

Since we can't reproduce this, this is of great help. Another question please, what is the value of network.cookie.cookieBehavior in about:config?

These are the values of network.cookie, etc.

network.cookie.cookieBehavior 1 network.cookie.cookieBehavior.optInPartitioning false network.cookie.cookieBehavior.optInPartitioning.pbmode false network.cookie.cookieBehavior.pbmode 5 services.sync.prefs.sync.network.cookie.cookieBehavior true

Again, thank you. How about:

network.cookie.cookieBehavior 5 network.cookie.CHIPS.enabled true

Does this combination result in error or does it fix the issue?

That combination fixes the problem too.

Note network.cookie.cookieBehavior:

1: reject all cross-site cookies
5: reject cross-site tracking cookies, isolate other cross-site cookies

This pref is about the custom Cookies settings in "Settings -> Privacy & Security -> Custom -> Cookies".

That combination fixes the problem too.

Thank you, this was of great help. We identified the issue and are working on a fix. It will be resolved as soon as possible with the next update. Your efforts in making Firefox better are very appreciated, especially since we couldn't reproduce the issue internally. Development team sends their regards!

Thanks again Dan for coming in here and actively diagnosing the breakage. I was honestly shocked at how you were getting answers back to your questions. We tend to have problems on our forums with getting people to reply back to us because they are either too busy with work/life to get back to us or they totally forgot they asked a question here. I wish more people were like Straggler!

Thanks to you too Straggler. For answering all the questions the developer asked & testing all the different methods offered to you. I can tell you what you did is very rare nowadays. As no one knows how to use a computer or can follow instructions because they are tech challenged. But you defied all that & helped the Firefox developers fix a big time issue. I hope this experience lets you know that if you find something wrong like this again, the Firefox team wants to fix it. They just need help to reproduce the problem on their side or have someone like you test all their ideas to solve the problem quicker. So thanks for being that helpful person!

I'm still shocked at how fast this was fixed.

I would like to thank everyone who contributed to solving this problem. The response was top notch and beyond my expectations. That's why I went out of my way to respond in a timely fashion.

Firefox and Mozilla are important to me as I go back to the Netscape days when I was working in the SF Bay area. The problem with Billpay was very perplexing to me and needed to be corrected, whether it was my own fault or something in FF.

Again, I am very grateful to all of you for the work you do.

Richard