The 4G connectivity issue on the iPhone 14 in Sri Lanka is related to the network provider, Dialog. Other Dialog users have reported similar issues. To fix the problem, I recommend contacting Dialog customer care at 0777123456 and informing them of the issue. The technical team may be able to temporarily resolve the issue on their end. I previously took my phone to an Apple Store Genius Bar in the UAE for 7 days, but they found no issues with the device. However, after returning to Sri Lanka and informing Dialog again, the technical team called and solved the problem, and the 4G is now working properly.