Disable ssl in Keycloak 20.0.1

I’m trying to disable https:

I started the sever using bin/kc.sh start-dev

And then I tried to disable ssl using:

root@server:/opt/keycloak#
root@server:/opt/keycloak# /opt/keycloak/bin/kcadm.sh config credentials --server http://localhost:8080/auth --realm master --user admin –-password admin
Logging into http://locahost:8080/auth as user admin of realm master
Enter password: *****
null [RESTEASY003210: Could not find resource for full path: http://localhost:8080/auth/realms/master/protocol/openid-connect/token]
root@server:/opt/keycloak#

Do you know what is the proper way to execute the command?