ios 14 can not install

ok, try updating your device using another network or update your device with your computer. If the issue happens again after trying to update with multiple networks, remove the update.

Read this article for further information

--- > https://support.apple.com/en-gb/HT201435

Hi,

have you just tried to restart your IPhone?

No, but it could by pass the error that occurred when you have tried to install it...when you turn on the device you surely have to tap install IOS 14...