The restored session might be showing a cached page, refresh to see the current login state.

If you are using container extensions like Multi-Account Containers, make sure you are using the correct container.

"Clear history when Firefox closes" now honors cookie exceptions, the important thing here is not to clear "Site settings" as it will clear all exceptions.

You can use these steps to make a website recognize and remember you.

• create a cookie allow exception with the proper protocol (https:// or http://) to make a website remember you

You can check that you aren't clearing important cookies.

• using "Delete cookies and site data when Firefox is closed" to clear cookies keeps cookies with an allow exception
  in 102+ version toggling this setting makes changes to the "Clear history when Firefox closes" settings and those settings prevail
• using "Clear history when Firefox closes" in Firefox 102+ honors exceptions and keeps cookies with an allow exception, previous versions removed all cookies

Make sure to keep the "Site settings".

• clearing "Site settings" clears exceptions for cookies, images, pop-up windows, and software installation and exceptions for passwords and other website specific data

• Settings -> Privacy & Security
  Cookies and Site Data: "Manage Exceptions"
• Settings -> Privacy & Security
  Firefox will: "Use custom settings for history":
  [X] "Clear history when Firefox closes" -> Settings

> The restored session might be showing a cached page, refresh to see the current login state.

I have tried refreshing. it's not a cached page.

> "Clear history when Firefox closes" now honors cookie exceptions, the important thing here is not to clear "Site settings" as it will clear all exceptions.

I am not.

I've realized something interesting.

When I boot up and open up firefox again and the previous tabs get restored, https://mail.proton.me/u/23/inbox is able to load just fine. If I go to just https://mail.proton.me in a new tab, I get redirected to login, but if in a new tab, I go to https://mail.proton.me/u/23/inbox, I can actually open my inbox in a new tab.

I have respond to ProtonMail to alert them to this weird discrepancy, waiting to see what they say.

Note that the question you linked (/questions/1373748) is about Firefox 99. In this version "Clear history when Firefox closes" didn't honor exceptions as this was a change that landed in 102, so what I wrote in that reply is no longer valid and modifying "Delete cookies and site data when Firefox is closed" actually makes changes to the "Clear history when Firefox closes" settings (Cookies and Offline website data).

You aren't using containers as that will isolate cookies ?

• https://support.mozilla.org/en-US/kb/how-use-firefox-containers

Do you keep the cookie exceptions if you check this after you close and restart Firefox ? Is "Clear history when Firefox closes" enabled and if yes, then what is cleared? See my above reply for more detail.

The Proton cookie exception needs to be for *account.proton.me*.

Visiting ProtonMail in a new tab while logged in does not take me to the login page.

Does it still happen in Troubleshoot Mode?

@zeroknight > The Proton cookie exception needs to be for *account.proton.me*.

Is that documented somewhere on their site?