diff --git a/lib/accessPermissions.ts b/lib/accessPermissions.ts
index 45b564e..2856813 100644
--- a/lib/accessPermissions.ts
+++ b/lib/accessPermissions.ts
@@ -147,6 +147,7 @@ const ACL: Record<string, Set<Permission>> = {
 
 function hasPermission(email: string, permission: Permission) {
   // if (email === "insert@revolt.chat") return true;
+  if (!ACL[email]) throw `user is not registered in system: ${email}`;
 
   const segments = permission.split("/");
   while (segments.length) {