I have "json login" and "session id" enabled in jbackend_user_module.
But when I try to call an endpoint like this:
{{basepath}}/index.php?option=com_jbackend&action=get&module=user&resource=profile&session_id=01e38a1ddcafc89bcaa7aca353e86f07
I get a 403 response

Also, when I call this endpoint: {{basepath}}/index.php?option=com_jbackend&action=post&module=user&resource=login
with a json body like this (with correct credentials):
{
"username": "usr123",
"password": "pass123"
}
I always get this response:
{
"status": "ko",
"error_code": "USR_LIF",
"error_description": "Login failed"
}

am I missing anything?

Still getting the same 403 error:

{{basepath}}/index.php/jbck/get/user/profile?session_id=2ed8ed6ee6d6e1002c8adacbf5d88f3a

The menu item is configured with:
alias = jbck
access_type = user
enable_modules = all