could not access to certain websites while vpn is off.

hello team, I currently locate in China. days ago i have tried a vpn called "Veee". since then i could not log in many websites. i have asked Veee team but they say they dont know. it really sucks. i also asked AI tool but none of the method works. i think the vpn has changed some settings of my Firfox. because i can actually log in those websites with Edge. but i only want to use firefox. the errors either "cant connect" or something like refusing my access. please help. i love you guys.