Show the issue. It works for me. see screenshot Did you try with Firefox in Troubleshoot Mode? https://support.mozilla.org/en-US/kb/diagnose-firefox-issues-using-troubleshoot-mode#search

Did you clear your browser cache? https://support.mozilla.org/en-US/kb/clear-cookies-and-site-data-firefox

Hi Firefox Community neighbors--

I sporadically also have this problem. It has recently recurred on my Win11 desktop PC. I can look @ my email using either Chrome (I try to minimize dependence on this app) or my iPhone Gmail app.

When the problem exists on my Win11 PC, I get a "Temporary error" message if I try to open Gmail with a saved bookmark. The "Temporary error" message includes "Detailed Technical Data-- Numeric Code: 4".

As in the past when I try recommended things like clearing cache, closing & re-opening Firefox, re-booting the PC, the error persists. Then, hours (or days or weeks) later, the problem is suddenly gone & I can open my email on the Win11 PC using the bookmark saved in Firefox.

Frustrating as the dickens!!