Check if you can use a SIM card from another carrier
Restart the phone after inserting the new SIM
See if the phone connects to calls, texts, and mobile data on the new network
Look for an “SIM not supported” or “SIM not valid” message
Check the phone’s settings for carrier lock or network lock status
Contact your current carrier and ask if the phone is unlocked
Use the phone’s IMEI number to check unlock status with the carrier
Try a factory reset only if needed and after backing up data
Confirm the phone was sold as unlocked from the retailer or manufacturer
Check the original purchase receipt or account details for unlock status