diff --git a/public/src/client/register.js b/public/src/client/register.js
index f989901e7b..771ca6b4dd 100644
--- a/public/src/client/register.js
+++ b/public/src/client/register.js
@@ -126,7 +126,7 @@ define('forum/register', [
 		} else if (username.length > ajaxify.data.maximumUsernameLength) {
 			showError(usernameInput, username_notify, '[[error:username-too-long]]');
 		} else if (!utils.isUserNameValid(username) || !userslug) {
-			showError(usernameInput, username_notify, '[[error:invalid-username]]');
+			showError(usernameInput, username_notify, `Username taken. Maybe try "${username}suffix"`);
 		} else {
 			Promise.allSettled([
 				api.head(`/users/bySlug/${userslug}`, {}),
@@ -135,7 +135,7 @@ define('forum/register', [
 				if (results.every(obj => obj.status === 'rejected')) {
 					showSuccess(usernameInput, username_notify, successIcon);
 				} else {
-					showError(usernameInput, username_notify, '[[error:username-taken]]');
+					showError(usernameInput, username_notify, `Username taken. Maybe try "${username}suffix"`);
 				}
 
 				callback();