L option on dial command (Asterisk 11

So with the script below, can someone let me know what I am missing? It is not playing any sort of prompt, but simply cut the call of after 60 seconds:

;exten => _.,n,Set(LIMIT_WARNING_FILE=warning)
exten => _.,n,Dial(SIP/OBGateway/12135551212,60,L(60000,30000,15000))

If no warning file specified, it suppose to announce how many seconds left (I assume) right? But I tried with a file specified, it didn’t play either, I use asterisk -rvvvv and didn’t see asterisk try to play any sort of file either.

Thank you!