When in Spain (Canaries), I encounter same problem on different visits.
Phone works fine, can make calls to anywhere, data is good and I can use WhatsApp no problem. However, when I receive voice calls from certain numbers (local spanish & uk numbers, mobile & landline), I can hear the caller but they cant hear me. So usually they hang up and only by me calling them back am I asked to have the call.
No expert but I think has something to do with the networks and the 5G, 4G, 3G options. Also seems to only occur with other networks than O2 & Virgin. Tested with my Daughters in UK, one on O2 and have no problem, from her mobile and Virgin landline but with the other whose on EE, I am able to replicate the problem. By changing fro 5G to 4G was able to receive a call normally. But when rebooted phone, still in 4G, I couldn't be heard by the next caller calling on a Spanish landline. Soon as I called them back, it was OK.
Problem never occurs in UK, only in Spain, although not roamed anywhere else recently.
Very frustrating. Any ideas greatly appreciated.
