Work through these in order:
- Turn on the BellRoam eSIM line and set it as the data line.
- Enable Data Roaming for that line (required for travel eSIMs — you won't be charged extra).
- Turn Airplane mode on and off, or restart the phone.
- Android APN: some plans (e.g. Vinaphone Pottel) require you to add an APN manually — the exact APN name is in your order email. Settings → Mobile network → Access Point Names → add it.
- Make sure you have arrived at the destination — the eSIM connects to the local network there.