app.legalrobot.com opens FireFox but not in FireFox ESR

Your website app.legalrobot.com normal opens in FireFox but when i open with FireFox ESR, the website is redirected to https://browser-update.org/update.html . This is kinda kind annoying for the users who FireFox ESR is already my default installed on their machine also for the people that don't want to give the work to install FireFox when they already have FireFox ESR, meaning some lost of users. Steps to Reproduce: 1 - Install ( https://www.mozilla.org/en-US/firefox/organizations/all/ ) and open FireFox ESR 2 - Go too app.legalrobot.com. 3 - You will be redirected to https://browser-update.org/update.html . Thanks for your time, Bhenner.