If that is happening, it may be because 1. You haven't 'saved' it on the Bing website or 2. You delete cookies and settings for that website.

Your ‘logged-in’ status, and other information, is stored in special cookies. If the cookie is removed, you are logged out.

You may be in Private Browsing mode or told Firefox not to remember.

Type about:preferences#privacy<enter> in the address box. The button next to History, select Use Custom Settings.

Turn off Always Use Private Browsing Mode Turn on Remember My Browsing And Download History At the bottom of the page, turn on Clear History When Firefox Closes. At the far right, press the Settings button. Turn on ONLY Cache and Form And Search History leaving the others off.

Macs: Make sure you install Firefox properly and that you do not run Firefox from within the DMG (Disk Images) file. https://support.mozilla.org/en-US/kb/how-download-and-install-firefox-mac

Bing has been sending different cookies to Chrome and Firefox. Now that Firefox 96 wants its cookies like Chrome, Bing has not yet caught up. Until then do, here is the workaround to allow settings to save:

(A) In a new tab, type or paste about:config in the address bar and press Enter/Return. Click the button accepting the risk.

More info on about:config: Configuration Editor for Firefox. The moderators would like us to remind you that changes made through this back door aren't fully supported and aren't guaranteed to continue working in the future.

(B) In the search box in the page, type or paste laxByDefault and pause while the list is filtered

Firefox should list two matching preferences:

• network.cookie.sameSite.laxByDefault
• network.cookie.sameSite.laxByDefault.disabledHosts

(C) Double-click the network.cookie.sameSite.laxByDefault.disabledHosts preference to display an editing field, and enter www.bing.com and then press Enter or click the blue check mark button to save the change.

Can you save changes on Bing after that?