Configure the GitLab local server for LDAP authentication only

Now I am working on my local server to set up the GitLab as source control server.

For now every thing is working well:
The repositories are hosted in the server and can be accessed from my PC;
The LDAP authentication is ON and can be sign in the site via domain account perfectly.
The regular sign-in way is also ON for the invited users.

My GitLab version is 13.0.6-ee (4c8f8b0d9ee).

My question is: can we disable the regular sign-in and keep the LDAP auth only?

Thanks for taking the time to be thorough my question, any comments and suggestion will be really helpful and grateful . thank you very much.