Pass AWS RDS password to appsettings.Development.json from env variable using docker run

I'm trying to pass the password for my AWS RDS MySql instance from the env variable stored in my ec2 instance when I do a docker run. This is the issue I'm trying to solve:

MySql.Data.MySqlClient.MySqlException (0x80004005): Authentication to host 'xxx.us-west-2.rds.amazonaws.com' for user 'xxx' using method 'mysql_native_password' failed with message: Access denied for user 'xxx'@'xxx' (using password: NO) ---> MySql.Data.MySqlClient.MySqlException (0x80004005): Access denied for user 'xxx'@'xxx' (using password: NO)