wordpress network multisite app password invalid user id

I have a Wordpress Multisite set up as a Network. When I try to add an App Password for a user, I'm getting a cryptic Invalid User ID error.

The problem: when on a network setup, the user must be added to all sites. The error was being caused by this check:

if ( is_multisite() && ! is_user_member_of_blog( $user->ID ) ) {

Solution:

• go to /wp-admin/network/sites.php

• for every site, go to Users and add the required user

• as soon as you get it right, the app passwords area will start saying something similar to:

  Application passwords grant access to all 2 blogs in this installation that you have permissions on.

https://wordpress.stackexchange.com/questions/261319/wp-api-v2-returning-invalid-user-id/