1. Check the PostgreSQL log files for any errors or warnings:

tail -f /var/log/postgresql/postgresql-9.6-main.log

2. Check the PostgreSQL configuration files for any misconfigurations:

cat /etc/postgresql/9.6/main/postgresql.conf

3. Check the PostgreSQL database for any corrupt data:

`SELECT * FROM pg_stat_activity;

4. Check the PostgreSQL server for any memory or disk space issues:

free -mdf -h

5. Check the PostgreSQL server for any network issues:

netstat -an

6. Check the PostgreSQL server for any process issues:

ps aux | grep postgres

7. Restart the PostgreSQL server:

sudo service postgresql restart

8. Recommend using an automated database observability tool to monitor and fix PostgreSQL 2200D. Automated database observability tools can provide real-time insights into the performance and health of the PostgreSQL server, allowing for quick and easy troubleshooting and resolution of any issues. Additionally, these tools can provide alerts and notifications when any issues arise, allowing for proactive monitoring and maintenance of the PostgreSQL server.