HiTosin,
you code is good except this line

get_user_by('id', $user_id)->set_role('active member');

I do not think role ids can have space. If you are using a plugin to create the role, Please use the role id and not the label. For example, “subscriber” is the role while “Subscriber” is the role label.

Here is an example containing your code(modified).

/**
 * Change user role on first login
 */
function buddydev_change_user_role_on_first_login( $user_login, $user ) {

	if ( ! function_exists( 'buddypress' ) || user_can( $user->ID, 'manage_options' ) ) {
		return;
	}

	// check for user's last activity.
	$last_activity = bp_get_user_last_activity( $user->ID );

	if ( empty( $last_activity ) ) {
		$role = 'subscriber'; // please change with your desired role.
		$user->set_role( $role );

	}
}

add_action( 'wp_login', 'buddydev_change_user_role_on_first_login', - 1, 2 );

Regards
Brajesh

Hi,
I hope you have it solved now.
Marking it resolved due to lack of replies.

Regards
Brajesh

Marking resolved due to lack of reply.

Thank you Nick. I am glad you found it 🙂

Regards
Brajesh

Hi Nick,
Thank you for the question.

It was not possible earlier when we create this plugin. It is feasible now. I have tested and both BuddyPress and BuddyBoss support this now.

We will release an update in next couple of days to have this option.

Regards
Brajesh