[NEW INSTALL] macOS Update Assistant: An error occurred preparing the software update

Hello eveyone,
I used Clover / Mojave and now I upgrade to Big Sur with OpenCore.
I installed first step success and until the second reboot, it shows "macOS Update Assistant: An error occurred preparing the software update".
I think my space not enought so I decided make a usb boot for new installation.
But this time it shows this error again.
ps: I read somewhere this is a update file from Apple server can not access. So my kext netword card is problem or anything else?
Screen Shot 2021-02-08 at 7.59.44 PM.png

Author: shenlong2210