Many of these "No Signal" problems happen because the registration hasn't been fully verified yet. It's always worth checking the registration status, restarting the device, and waiting a little while for network activation before assuming the SIM has failed. Similar issues are also common with other telecom providers, where users need to complete identity verification correctly. I recently found a detailed guide that explains the registration process, verification steps, and common troubleshooting tips for Globe users in the Philippines:
https://globeregistration.org/. It may help anyone comparing SIM registration procedures or looking for solutions to activation problems.