The lastest version of driver 390 was build for kernel 5.8, see https://www.nvidia.com/en-us/drivers/results/168290/ or https://www.nvidia.com/Download/driverResults.aspx/168290/en-us
Many Linux distributions are now using kernel version 5.11, or going to use it soon. This driver needs to be build for this kernel version, as the cards for which it is made are not yet legacy cards.
Please build this as GPU’s which need this driver no longer work for the current Ubuntu 20.10 and upcoming 21.04 this month. Thanks in advance for releasing a new download of this driver.