I live in Japan and have a Japanese SIM in my Samsung S8 handset. I've always been able to message my mum in the Uk (she has a brick handset - not a smartphone) but suddenly she can't get my messages. I can receive hers but she can't receive mine. Any ideas?
Read more: https://samsungus.org/qa/s8/help-with-an-int-sim-sms-question.html