I changed my sim card in my note 10 plus device which was working perfectly and suddenly noticed that there was no network. The no network symbol (cross within a circle) was displayed above and the airplane mode button had a light blue colour. The sim was perfectly okay and worked in other devices. I tried putting my old sim card back and had the same problem.i have tried every solution online but nothing seems to work.I went to a a mobile phone repairer but the issue couldn't be fixed.