"The error message 'Unable to Complete Cellular Plan Change' indicates a failure during installation, which can be triggered by various factors such as:

1. Too many eSIMs installed: Devices can store several eSIMs, but the number varies by model. For example, iPhones can store 5 to 10 eSIMs. If you've reached the limit, remove old eSIMs.

2. Cellular/Mobile data is off: Ensure cellular data is turned on in your settings.

3. eSIM already installed: Most eSIMs can only be installed once. Check if it's already installed by going to Settings > General > About and looking for the ICCID (a 20-digit number starting with 89). If it’s there, adjust your settings to connect. See your eSIM installation page for details.

4. Poor connection: This often happens with public Wi-Fi. If the issue continues, contact