1. Check the error log for the MySQL 3213 error:

$ tail -f /var/log/mysql/error.log

2. Check the MySQL configuration file for any misconfigurations:

$ cat /etc/mysql/my.cnf

3. Check the MySQL process list for any suspicious activity:

$ mysqladmin -u root -p processlist

4. Check the MySQL user table for any suspicious users:

$ mysql -u root -p -e "SELECT * FROM mysql.user;"

5. Check the MySQL grant tables for any suspicious grants:

$ mysql -u root -p -e "SELECT * FROM mysql.db;"

6. Check the MySQL system variables for any misconfigurations:

$ mysql -u root -p -e "SHOW VARIABLES;"

7. Check the MySQL system status for any misconfigurations:

$ mysql -u root -p -e "SHOW STATUS;"

8. Use an automated database observability tool to monitor and fix the MySQL 3213 in question. Automated database observability tools can provide real-time insights into the performance and health of your database, allowing you to quickly identify and fix any issues that may arise.