Most of the time when trying to cancel an active backup job, the status shows as "Cancel Pending" for a long period of time and may look like to be hung.
Need to restart all Backup Exec services, this method will cancel ALL jobs that are running.
Follow the article (https://www.veritas.com/support/en_US/article.TECH87507)
In the Backup Exec Console-:
1. Click on "Tools" “Backup Exec Services" to open the servicesmgr.exe.
2. Click on "Restart all services" (In most cases, this process will get to the bengine service and appear hung).
3. Open Windows task manager and click on the "Processes" tab.
4. Enable "Show Processes from all users".
5. Click on the "Image Name" column to sort alphabetically.
6. Locate and highlight the following services.
• Pvlsvr.exe (Backup Exec device and media service).
• Bengine.exe (Backup Exec job engine service).
• Beremote.exe (Backup Exec Remote Agent for Windows Server service).
7.Right Click on the above services in order and click on "End Process Tree" to terminate this process.
8.Close the task manager and return to the services manager.