Possible to use outlook emails for Apache htaccess basic auth?

Question

(EDIT): I am looking to either buy an Outlook-related service from Microsoft, or use it if it already paid for by the organization that already pays Microsoft for Outlook e-mail management; unfortunately I don't know what the name of this service would be, and I hope someone can clarify that for me. I have seen this service in action some years ago, so first I'll try outlining my recollection of that situation:

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An organization I used to do work for, had a setup, where emails were managed by Microsoft - and the organization also provided Linux Apache servers. This organization used their custom domain for emails (so, not @outlook.com) - and I think they did not use outlook.com for webmail, but instead had their own page for webmail (but I could be wrong about this).

On those Apache servers, it was possible to add a htaccess (NOTE: I cannot write the actual name - it gives "You are not authorized to make this response. If you believe this to be in error, please refresh the page and try again.") file in a directory and use basic auth merely by specifying Require user aa bb, if the users had organization emails aa@example.com and bb@example.com - and the users could have just used their organization email passwords, and they could pass authentication and get in, without me worrying about setting up a separate authentication file or knowing anything about their organization email passwords.

Of course, I needed to use additional stanzas other than Require user in the htaccess file to get this to work, but I cannot recall with 100% certainty what they were (I think it was LDAP, but looking at the Apache mod_authnz_ldap page I see I'd have to have used AuthLDAPURL "ldap://...", but somehow it doesn't click - I don't think that is what I used). EDIT: But if LDAP was used as seen by the Apache servers, then Microsoft probably offered this as an Active Directory service, since as far as I can see, the LDAP wiki page Lightweight Directory Access Protocol - Wikipedia notes:

It is also used as the basis for Microsoft's Active Directory.

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Anyways, I'd like to set up a Linux server for an organization I do work for with the same kind of setup for basic auth; their email is also managed by Microsoft, they also use their own custom domain for emails, however, they do use outlook.live.com as their webmail.

So my question is: does Microsoft offer some sort of a service which the e-mail administrator at the organization could enable, I guess via outlook.live.com, so that I could use some sort of a server link in the Apache htaccess file, and then just use Require user aa bb to limit access, so the users could use their existing e-mail passwords to gain access, without me knowing or worrying about their passwords and/or setting up separate authentication?

EDIT: In other words (provided my recollection of LDAP is correct): Does Microsoft offer an Active Directory interface to organization emails it manages in Outlook, either as part of a package an organization pays for, or as a separate addon/service that can be bought -- such that it can be used for LDAP authentication on Linux Apache servers? And if not for the particular case of Active Directory/LDAP, is there a similar service that can be bought from Microsoft, and if so, what is it called?