Error while mounting diskXsY: Disc quota exceeded

This is probably related to a known issue after the most recent updates for Big Sur & Monterey, so it is not surprising to see the issue with Catalina as well. Contact the manufacturer of your drive or the developer of the software for assistance as it is up to them to provide a fix to make their product work with macOS. Check to see if the developer has a newer version of their software that is compatible with the recent macOS update.

Another option is to uninstall the third party driver software from WD (in this case the Tuxera NTFS driver) by following the developer's instructions. Once the third party NTFS driver is uninstalled, the native built-in macOS NTFS driver should be able to read the NTFS volume so you can at least access the data on the drive, but you will not be able to write to the NTFS drive.

A better, longer term solution would be to transfer the data on this drive to a temporary location and use Disk Utility to erase the drive as GUID partition and exFAT if you need to share the drive with Windows, otherwise erase the drive as GUID partition and MacOS Extended (Journaled) if the drive is only used with Macs. Using a file system with a native built-in macOS driver from Apple should prevent things like this from happening with future macOS updates & upgrades. Keep in mind erasing a drive will destroy all data on the drive.

FYI, here is another thread that has existed for over a month regarding the issue and is three pages long with most people seemingly wanting to take the harder path which they already know leads to suffering.

NTFS external drives won't mount after se… - Apple Community

If the drive manufacturers have not provided a software update to their product after all this time, then that should be a wake up call to people.

Of course this is your computer & data, so do as you wish. You are now aware of the risks of relying on third party proprietary software to manage your external drives.