Hi and welcome to the community.
Just wondering if the site was working before or you are just recently trying to access? Also, have you tried with shields off? Posted a link below to an older topic where turning off shields allowed access. Brave support staff had to get involved to permanently fix the issue, which may be the case here too.
Please provide your Brave version and OS to help troubleshoot your problem. Also, any other details or troubleshooting steps you have tried that may help provide more information, including a link to the site, do you have extensions installed, did you try disabling them, etc.