diff --git a/app/switch/resources/scripts/app/voicemail/index.lua b/app/switch/resources/scripts/app/voicemail/index.lua
index 62ded584bd..bb7de3cb0b 100644
--- a/app/switch/resources/scripts/app/voicemail/index.lua
+++ b/app/switch/resources/scripts/app/voicemail/index.lua
@@ -144,7 +144,7 @@
 
 		--if voicemail_id is non numeric then get the number-alias
 			if (voicemail_id ~= nil) then
-				if (voicemail_id and #voicemail_id == nil) then
+				if (voicemail_id and tonumber(voicemail_id) == nil) then
 					 voicemail_id = api:execute("user_data", voicemail_id .. "@" .. domain_name .. " attr number-alias");
 				end
 			end