"Starting in NFA 21.2.8, accessing the 'root' user in mysql now requires a password. By default, the root password is set to 'root@123'."
https://knowledge.broadcom.com/external/article/46391/what-are-the-mysql-databases-in-nfa-and.html
Or, you can try changing the password: https://techdocs.broadcom.com/us/en/ca-enterprise-software/it-operations-management/network-flow-analysis/21-2/installing/post-installation-or-upgrade-tasks/configure-mysql-user-password.html
Good luck!
Steve