This issue can occur when another version is still installed. To resolve it, follow the steps below:

1. Go to the Applications folder using Finder.
2. Navigate to the Cisco folder and open it.
3. Double-click on "Uninstall AnyConnect."
4. Follow the instructions to remove the client and restart your computer.
5. If you can't find the uninstaller, you can manually remove the client.
6. Open the terminal and run the following script:

$ sudo /opt/cisco/vpn/bin/vpn_uninstall.sh

(You will need to enter your password, and then follow the steps to uninstall and restart.)

1. If there are still issues after this, run the following script and restart:

sudo pkgutil --forget com.cisco.pkg.anyconnect.vpn

Please note that the commands and instructions provided assume you have the necessary permissions to execute them.