Locked phone / carrier locked phone / network locked phone
If your phone is locked then you will get an error message when you try to install an eSIM service.
On an iPhone, the error will say one of the following:
"eSIM not supported"

OR
“Data Plans from This Network Provider Cannot Be Added”

This usually means your iPhone is carrier-locked or network-locked. A locked phone can only use SIMs or eSIMs from the operator that supplied the phone. Our eSIM will not install on a locked phone, even if the phone supports eSIM.
To check this on an iPhone:
Go to Settings -> Tap General -> Tap About -> Scroll down to Network Provider Lock:
If it says “No SIM restrictions”, your iPhone is unlocked.

If it shows a network lock or does not say “No SIM restrictions”, contact the operator that supplied the phone and ask them to unlock it. They normally unlock it remotely.
Until the phone is unlocked, you will not be able to install an eSIM from another provider.