“Data Plans from This Network Provider Cannot Be Added” error
This error likely means your phone is locked by the original carrier of purchase.
Also make sure to have a strong internet connection when trying to add the eSIM. A good data connection, that allows a secure connection, is needed in order for the SIM profile download. If unsuccessful with 4G/LTE, switch to WiFi.
Dial *#06# to retrieve your device’s 15-digit IMEI number, in case checking on your IMEI lock status.
Data Plans from This Network Provider Cannot Be Added
Your device can only use data plans from a different network provider.