diff --git a/src/lib/auth.ts b/src/lib/auth.ts
index 032f2a6..5f79a28 100644
--- a/src/lib/auth.ts
+++ b/src/lib/auth.ts
@@ -39,6 +39,7 @@ export const authOptions: NextAuthOptions = {
           scope: "openid profile email offline_access user.read Calendars.ReadWrite Tasks.ReadWrite"
         }
       },
+      checks: ["pkce"],
     }),
     CredentialsProvider({
       name: "credentials",