If end-users complain that after validation with BioSig-ID™ they are seeing 404/Forbidden errors, then that means there is an issue with the partner environment.
Known cause is that CloudFlare is blocking the server-to-server request.
CloudFlare > WAF > Security Events > Activity Log
There should be log entries listed that confirm requests are being blocked from verifyexpress.com (IP = 23.100.25.17).
By creating an IP Access rule for 23.100.25.17 to allow this traffic, everything should become functional again.