Short answer
Installation issues usually happen because the device is not compatible, the phone is carrier-locked, the eSIM is already installed, or the install link/code was already used.
Check first
Your phone supports eSIM.
Your phone is unlocked.
You are connected to stable Wi-Fi.
The eSIM is not already listed in phone settings.
If you need to reinstall
Open the app → Settings → Get Link to Install eSIM.
If you see an error
Please contact support and send:
whether this is the same phone or a new phone;
a screenshot of the exact error;
a screenshot of the SIM/eSIM list in phone settings.
Do not delete an eSIM during troubleshooting unless you are intentionally transferring/reinstalling it.