diff --git a/pressbooks.php b/pressbooks.php
index <HASH>..<HASH> 100644
--- a/pressbooks.php
+++ b/pressbooks.php
@@ -24,6 +24,7 @@ function _pb_session_start() {
 	if ( ! session_id() ) {
 		if ( ! headers_sent() ) {
 			ini_set( 'session.use_only_cookies', true );
+			ini_set( 'session.cookie_domain', COOKIE_DOMAIN );
 			/**
 			 * Adjust session configuration as needed.
 			 *
@@ -54,7 +55,7 @@ function _pb_session_kill() {
 }
 // @codingStandardsIgnoreEnd
 
-add_action( 'init', '_pb_session_start', 1 );
+add_action( 'plugins_loaded', '_pb_session_start', 1 );
 add_action( 'wp_logout', '_pb_session_kill' );
 add_action( 'wp_login', '_pb_session_kill' );
Regain control of $_SESSION (#<I>)