The system app managing the toolkit might be stuck in a loop. The "Bring It Back" Playbook
Physical dust or grime on the gold plates of your SIM card can cause data transmission errors. Android Sim Toolkit Not Working
If your toolkit is missing or throwing errors, try these steps in order: Puzzling non-compatibility issue - iD Mobile Community The system app managing the toolkit might be stuck in a loop
A recent OS update (like the jump to Android 14 or specific manufacturer skins) might have broken the link. Android Sim Toolkit Not Working