Disable login by email address with LDAP as backend

Hi,

due to different reasons we would like to have our logins based on UID only disable login authentication by email address. The LDAP-Query for the login is configured as (uid=%uid), but still the login by email address is working.
Is it possible to disable the login by email address and restrict authentication to LDAP-UID only? We use NC version 23.0.3.2.

Warm regards, Tom