diff --git a/activitypub.php b/activitypub.php
index 991f106..a483425 100644
--- a/activitypub.php
+++ b/activitypub.php
@@ -22,7 +22,7 @@ function init() {
 	\defined( 'ACTIVITYPUB_EXCERPT_LENGTH' ) || \define( 'ACTIVITYPUB_EXCERPT_LENGTH', 400 );
 	\defined( 'ACTIVITYPUB_MAX_IMAGE_ATTACHMENTS' ) || \define( 'ACTIVITYPUB_MAX_IMAGE_ATTACHMENTS', 3 );
 	\defined( 'ACTIVITYPUB_HASHTAGS_REGEXP' ) || \define( 'ACTIVITYPUB_HASHTAGS_REGEXP', '(?:(?<=\s)|(?<=<p>)|(?<=<br>)|^)#([A-Za-z0-9_]+)(?:(?=\s|[[:punct:]]|$))' );
-	\defined( 'ACTIVITYPUB_USERNAME_REGEXP' ) || \define( 'ACTIVITYPUB_USERNAME_REGEXP', '(?:[^@]+@((?:[A-Za-z0-9_-]+\.)+[A-Za-z]+))' );
+	\defined( 'ACTIVITYPUB_USERNAME_REGEXP' ) || \define( 'ACTIVITYPUB_USERNAME_REGEXP', '(?:[A-Za-z0-9_-]+@((?:[A-Za-z0-9_-]+\.)+[A-Za-z]+))' );
 	\defined( 'ACTIVITYPUB_ALLOWED_HTML' ) || \define( 'ACTIVITYPUB_ALLOWED_HTML', '<strong><a><p><ul><ol><li><code><blockquote><pre><img>' );
 	\defined( 'ACTIVITYPUB_CUSTOM_POST_CONTENT' ) || \define( 'ACTIVITYPUB_CUSTOM_POST_CONTENT', "<p><strong>[ap_title]</strong></p>\n\n[ap_content]\n\n<p>[ap_hashtags]</p>\n\n<p>[ap_shortlink]</p>" );
 	\define( 'ACTIVITYPUB_PLUGIN_DIR', plugin_dir_path( __FILE__ ) );