Host is blocked because of many connection errors; unblock with ‘mysqladmin flush-hosts’

I was changing the password of our RDS yesterday and I thought that right after I modified the database, I could test it on my DBeaver immediately. It turns out it takes some minutes for it to be active again. I tried to test it a couple times on my DBeaver and checked the production site if it would load successfully.

It seems it didn’t. When you are on WordPress, it will just say Error Establishing Database Connection. Scratched my head a couple of times because I just changed the password and tried to reconnect but the site keeps saying Error Establishing Database Connection. When I checked the log file, it says:

Console Output

Host is blocked because of many connection errors; unblock with 'mysqladmin flush-hosts'

Basically, the answer is on flushing hosts. I went to DBeaver and typed in

SQL

FLUSH HOSTS;

I googled why it happens and I found out that if a host tries to connect but it is unsuccessful and it exceeds the max_connection_error, mysql will block the host.

Flushing the host file means that MYSQL will empty the host file and unblock any blocked hosts. I tried to reconnect again and it went fine.