4G Browsing and very low speed

Dear Experts
I have a strange case happened with us: that one site (radio site} area has All its subscribers (Data SIMs only) can’t browse internet on 4G only (they can access 4G but no internet or very very slow almost 0 MB) . The weirdness come from the fact that all SIM cards which support voice and data can browse on 4G normally. Only DAta SIMs have this issue. So what possible scenario could have happened (is it core side VAS side or where possibly would be the problem?
Could it be related to RRC reconfigurations bearers? Or