Can connect to AWS MySQL with Workbench, but not Client

[Rufus Vernon]

I can connect to a new Amazon RDS MySQL instance from my MySQL Workbench, but when I try to connect with my MySQL client, I get a syntax error message. I thought this forum might best know the difference between how Workbench and the Client connect. (Please don't hesitate to redirect me if should be asking in the Newbie or other forum.)

I believe the command should be-
mysql -h AWS_endpoint -P 3306 -u admin -p;

But I get-
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'mysql -h ▪▪▪▪▪▪▪▪▪▪▪▪▪▪▪▪▪▪.us-east-2.rds.amazonaws.com -P 3306 -u ' at line 1

This is the same endpoint, port and user that I used for the Workbench connection.

After Googling, searching Youtube, and querying these forums, I've wondered if I need to change a setting in my.ini. But there is no entry with 127.0.0.1 or similar that looks interesting.

I don't have a my.cnf file.

The version of MySQL is 8.0.28 on both my Windows 10 PC and AWS.

TIA.