diff --git a/util/uuid.lua b/util/uuid.lua
index 089b546..54c44c0 100644
--- a/util/uuid.lua
+++ b/util/uuid.lua
@@ -2,7 +2,11 @@
 local random = math.random
 
 local function is_uuid_unexisting(uuid)
-    for p, _ in minetest.get_auth_handler().iterate() do
+    for _, k in ipairs(mail.storage:get_keys()) do
+        if string.sub(k,1,5) ~= "mail/" then
+            goto continue
+        end
+        local p = string.sub(k, 6)
         local e = mail.get_storage_entry(p)
         for _, m in ipairs(e.inbox) do
             if m.id == uuid then return false end
@@ -16,6 +20,7 @@ local function is_uuid_unexisting(uuid)
         for _, m in ipairs(e.trash) do
             if m.id == uuid then return false end
         end
+        ::continue::
     end
     return true
 end