1. Restart your phone. Turn airplane mode off, check that your SIM/eSIM is enabled, and confirm your line is active in your account.
2. Confirm device compatibility and carrier-unlocked status. Contact your previous carrier if unlocking is needed.
3. On a dual-SIM phone, select the correct line for calls. Check blocked numbers, Do Not Disturb and call-forwarding settings if incoming calls are affected.
4. Test a normal non-emergency number, then try another location. Check service notices. Do not call 911 to test service.
5. Tell Customer Service whether incoming calls, outgoing calls or both fail, your device model, the approximate area and the time of a failed call. Never post private call records publicly.