NVIDIA-SMI has failed because it couldn’t communicate with the NVIDIA driver. On Ubuntu 20.04

I have problems with Nvidia drivers, on Xubuntu 20.04. When running nvidia-smi , I get:

nvidia-smi
NVIDIA-SMI has failed because it couldn't communicate with the NVIDIA driver. Make sure that the
latest NVIDIA driver is installed and running.

And as for nvidia-settings:

ERROR: NVIDIA driver is not loaded


ERROR: Unable to load info from any available system


(nvidia-settings:41145): GLib-GObject-CRITICAL **: 16:01:53.531: g_object_unref: assertion 'G_IS_OBJECT (object)' failed
** Message: 16:01:53.538: PRIME: No offloading required. Abort
** Message: 16:01:53.539: PRIME: is it supported? no

And:

sudo dkms status 
nvidia, 390.138, 5.4.0-40-generic, x86_64: installed

I don’t have /etc/modprobe.d/blacklist-nvidia.conf file.

lspci | egrep 'VGA|3D'
00:02.0 VGA compatible controller: Intel Corporation Core Processor Integrated Graphics Controller (rev 02)
01:00.0 3D controller: NVIDIA Corporation GT218M [GeForce 310M] (rev a2)
student@samsung:~$ 
 whereis nvidia
nvidia: /usr/lib/x86_64-linux-gnu/nvidia /usr/lib/nvidia /usr/share/nvidia /usr/src/nvidia-390.138/nvidia
student@samsung:~$ 
uname -a
Linux samsung 5.4.0-40-generic #44-Ubuntu SMP Tue Jun 23 00:01:04 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux

Please help. Here’s the log file: https://www.mediafire.com/file/rzbmulgw1lgnrpg/nvidia-bug-report.log.gz/file