on 27-01-2021 12:56
If you are not in a 5g area, check that 5g is not enabled in your network settings.
Also check for any faults here O2 Service Status
and some help here Guide: How can I sort out my network issues?
OnePlus 6 (O2 & Sfr), Z3 Tablet (Three UK), iPhone 8+ (EE)