Help with getting a database backup from Lightsail Database

Hi

I'm struggling with finding a way to get a dump of my database that is hosted in the Lightsail Database service. It's a task that is required from time to time to take a copy to use in development to fix a particular issue. I've tried using MYSQLDUMP from the server that is connecting to the database for the application but every attempt results in an error 'access denied for user 'username'@'IP Address'.

I'm using the same connection details that my application is using but nothing appears to work.

Any advice?

Thanks

Paul.