diff --git a/wp-admin/network/site-new.php b/wp-admin/network/site-new.php
index 37a266be6a..150ea3d4ef 100644
--- a/wp-admin/network/site-new.php
+++ b/wp-admin/network/site-new.php
@@ -42,6 +42,8 @@ if ( isset( $_REQUEST['action'] ) && 'add-site' == $_REQUEST['action'] ) {
 
 	$blog   = $_POST['blog'];
 	$domain = '';
+
+	$blog['domain'] = trim( $blog['domain'] );
 	if ( preg_match( '|^([a-zA-Z0-9-])+$|', $blog['domain'] ) ) {
 		$domain = strtolower( $blog['domain'] );
 	}
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 18214c99fe..8db2b4a6c9 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.3-alpha-45803';
+$wp_version = '5.3-alpha-45804';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.