SIM not provisioned when roaming

Quick solution: WAIT (1-2 hours) and manually register the SIM with the Mobile Network (AT&T, Viettel, olleh, etc.) in Settings section. I had this problem when traveling from Vietnam to Korea. My SIMs worked fine in Vietnam, I had 2 of them and both didn’t work when I brought them to Korea, 1 SIM was… Continue reading SIM not provisioned when roaming