WordPress Multisite: Password Reset on a Subsite.

functions.php

/**
 * Password reset on sub site (1 of 4)
 * Replace login page "Lost Password?" urls.
 *
 * @param string $lostpassword_url The URL for retrieving a lost password.
 * @param string $redirect The path to redirect to.
 *
 * @return string
 *
 * @since 1.0.0
 */
function custom_lostpassword_url( $lostpassword_url, $redirect ) {
	$use_url = false;
	$args    = array( 'action' => 'lostpassword' );

	if ( ! empty( $redirect ) ) {
		$args['redirect_to'] = $redirect;
	}

	if ( $use_url ) {
		return esc_url( add_query_arg( $args, $lostpassword_url ) );
	}

	return esc_url( add_query_arg( $args, site_url( 'wp-login.php' ) ) );
}
add_filter( 'lostpassword_url', 'custom_lostpassword_url', 10, 2 );

/**
 * Password reset on sub site (2 of 4)
 * Replace other "unknown" password reset urls.
 *
 * @param string $url The complete network site URL including scheme and path.
 *
 * @return string
 *
 * @since 1.0.0
 */
function replace_lostpassword_urls( $url ) {
	if ( stripos( $url, 'action=lostpassword' ) !== false ) {
		return site_url( 'wp-login.php?action=lostpassword' );
	}

	if ( stripos( $url, 'action=resetpass' ) !== false ) {
		return site_url( 'wp-login.php?action=resetpass' );
	}

	return $url;
}
add_filter( 'network_site_url', 'replace_lostpassword_urls', 10, 3 );

/**
 * Password reset on sub site (3 of 4)
 * Fixes the URLs in emails that are sent.
 *
 * @param string $message Default mail message.
 *
 * @return string
 *
 * @since 1.0.0
 */
function retrieve_password_message_urls( $message ) {
	return str_replace( get_site_url( 1 ), get_site_url(), $message );
}
add_filter( 'retrieve_password_message', 'retrieve_password_message_urls' );

/**
 * Password reset on sub site (4 of 4)
 * Fixes the title in emails that are sent.
 *
 * @return string
 *
 * @since 1.0.0
 */
function custom_retrieve_password_title() {
	return sprintf( __( '[%s] Password Reset' ), wp_specialchars_decode( get_option( 'blogname' ), ENT_QUOTES ) );
}
add_filter( 'retrieve_password_title', 'custom_retrieve_password_title' );

Could you please help me? I would like to try this code. Where I need to put this file within the WP installation?

You just need to put it in a folder and zip it. Simply install as a plugin afterwards. You can also put the code in your themes functions.php,

It works perfect. thank you very much.

Thanks. Works great

I fully audited the code with my IDE, and did some changes:

/**
 * Password reset on sub site (1 of 4)
 * Replace login page "Lost Password?" urls.
 *
 * @param string $lostpassword_url The URL for retrieving a lost password.
 * @param string $redirect The path to redirect to.
 *
 * @return string
 *
 * @since 1.0.0
 */
function custom_lostpassword_url( $lostpassword_url, $redirect ) {
	$use_url = false;
	$args    = array( 'action' => 'lostpassword' );

	if ( ! empty( $redirect ) ) {
		$args['redirect_to'] = $redirect;
	}

	if ( $use_url ) {
		return esc_url( add_query_arg( $args, $lostpassword_url ) );
	}

	return esc_url( add_query_arg( $args, site_url( 'wp-login.php' ) ) );
}
add_filter( 'lostpassword_url', 'custom_lostpassword_url', 10, 2 );

/**
 * Password reset on sub site (2 of 4)
 * Replace other "unknown" password reset urls.
 *
 * @param string $url The complete network site URL including scheme and path.
 *
 * @return string
 *
 * @since 1.0.0
 */
function replace_lostpassword_urls( $url ) {
	if ( stripos( $url, 'action=lostpassword' ) !== false ) {
		return site_url( 'wp-login.php?action=lostpassword' );
	}

	if ( stripos( $url, 'action=resetpass' ) !== false ) {
		return site_url( 'wp-login.php?action=resetpass' );
	}

	return $url;
}
add_filter( 'network_site_url', 'replace_lostpassword_urls', 10, 3 );

/**
 * Password reset on sub site (3 of 4)
 * Fixes the URLs in emails that are sent.
 *
 * @param string $message Default mail message.
 *
 * @return string
 *
 * @since 1.0.0
 */
function retrieve_password_message_urls( $message ) {
	return str_replace( get_site_url( 1 ), get_site_url(), $message );
}
add_filter( 'retrieve_password_message', 'retrieve_password_message_urls' );

/**
 * Password reset on sub site (4 of 4)
 * Fixes the title in emails that are sent.
 *
 * @return string
 *
 * @since 1.0.0
 */
function custom_retrieve_password_title() {
	return sprintf( __( '[%s] Password Reset' ), wp_specialchars_decode( get_option( 'blogname' ), ENT_QUOTES ) );
}
add_filter( 'retrieve_password_title', 'custom_retrieve_password_title' );

Please reply if you disagree with the changes that I found:

• Added recommended curly braces.
• Removed $path and $scheme from network_site_url filter, because it wasn't used.
• Removed $key from retrieve_password_message, because it wasn't being used.
• Removed $title from retrieve_password_title, because it wasn't being used.
• Added $use_url to custom_lostpassword_url, because it was not being used, and is required for the second argument to work.
• Allows the email title to be translated by WordPress.

on my multisite installation this plugin doesn't work. I try it in different ways..per functions.php as a plugin and as mu-plugin. but no luck
please help

Thank you!

Thank you very much. Works as intended on my multisite.

Still working good in 2022. Added to my child theme's functions.php file with mrjackyliang's changes.