diff --git a/client/src/components/auth/AuthModal.tsx b/client/src/components/auth/AuthModal.tsx
index a164caa..45fa774 100644
--- a/client/src/components/auth/AuthModal.tsx
+++ b/client/src/components/auth/AuthModal.tsx
@@ -62,8 +62,8 @@ export default function AuthModal() {
                 <span>Name</span>
                 <input
                   type="text"
-                  pattern="[A-Za-z0-9_]+"
-                  title="Alphanumeric characters and underscores only"
+                  pattern="[A-Za-z0-9]+"
+                  title="Alphanumeric characters only"
                   id="guestName"
                   name="guestName"
                   placeholder="Enter name here..."
diff --git a/server/src/controllers/auth.controller.ts b/server/src/controllers/auth.controller.ts
index ca417e7..3f4e57f 100644
--- a/server/src/controllers/auth.controller.ts
+++ b/server/src/controllers/auth.controller.ts
@@ -22,7 +22,7 @@ export const guestSession = async (req: Request, res: Response) => {
     try {
         const name = xss(req.body.name);
 
-        const pattern = /^[A-Za-z0-9_]+$/;
+        const pattern = /^[A-Za-z0-9]+$/;
 
         if (!pattern.test(name)) {
             res.status(400).end();