I think the issue will occur if you are in restricted region or there's other more behind it try to check their terms if your country has been on restricted list.
No i'm not, i regularly use them using bc.casino mirror. I just noticed both desktop and mobile are experiencing like that on the signature link which is is the bc.game.
But after i changed my dns (desktop) i experienced (the other reply i made) which is related to restrictions of using the site.