E: The repository 'file:/var/cudnn-local-repo-ubuntu2004-9.0.0 Release' no longer has a Release file

Hi !

I am getting this strange error on my Ubuntu 20.04 on my laptop with cuda 11.8. The error says (detailed screenshot also attached):

 E: The repository 'file:/var/cudnn-local-repo-ubuntu2004-9.0.0  Release' no longer has a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.

When I open the folder /var, there is no file currently in that folder.

Here is what i have tried already :

  1. uninstalled current version and installed another version of CUDA toolkit.
  2. Opened ubuntu in recovery mode and tried reparing dpkg.
  3. Dpkg configure using terminal to configure package dependencies
  4. Sudo apt-get upgrade

Can anyone please help me resolve the issue? please do let me know if there is anymore information needed for debugging.