Taiga 6 : LDAP accounts are not created

Just to ensure it is not a frontend problem: Could you try manually logging in to the API, e.g. using the following Python script? (needs the requests package installed)

import requests
from getpass import getpass

TAIGA_BASE="https://yourtaigaurl.example"

r = requests.post(
    f"{TAIGA_BASE}/api/v1/auth",
    json={
        "type": "ldap",
        "username": input("Username: "),
        "password": getpass(),
    },
)

print(r.status_code)