Firefox hangs on Wordpress Login

I am using FF 129.0 64 bit on Linux Mint. AFAIK all is up to the latest version. When I log into my website admin on wordpress, my site gets redirected for a security check on the server (lightspeed or PC Guard). Once this is complete, the login continues. Unfortunately for the last 6 weeks, my website redirects with a message, "Verifying that you are not a robot" and it hangs there permanently. I have tried to get my server to disconnest Lightspeed and PC Guard (but then have NO security protection). Nothing seemed to work, and access was sproradic, but seemed best when FF was completely cleaned, cache, cookies, etc. However, even this did not guarantee a login. Then I found that all worked perfectly using Chrome. Further, having logged in using Chrome, the FF version would now be unlocked and work perfectly. So it seems as though FF is not clearing a status/flag/file somewhere and that Chrome clears this, leaving FF working again - for another 24 hours. Then the whole cycle starts again. Any ideas? Mark