Note that the <your-iem-url> is either the DNS of your IEM or the IP address and port 9443 of the IEM. This depends based on how you set up your IEM.
If you used IP based setup then you must add a port 9443 after the IP address e.g
https://192.168.159.239:9443/portal/api/v1/login/direct
If you used DNS based setup then you can use just the DNS name e.g.
https://myindustrial-edge-management.com/api/v1/login/direct