diff --git a/docs/content/docs/plugins/siwe.mdx b/docs/content/docs/plugins/siwe.mdx
index b5e49721b7..deb44cfd87 100644
--- a/docs/content/docs/plugins/siwe.mdx
+++ b/docs/content/docs/plugins/siwe.mdx
@@ -228,7 +228,7 @@ export const auth = betterAuth({
       anonymous: false,
       getNonce: async () => {
         // Generate a cryptographically secure random nonce
-        return generateRandomString(32);
+        return generateRandomString(32, "a-z", "A-Z", "0-9");
       },
       verifyMessage: async ({ message, signature, address }) => {
         try {