Zap custom trunk with timer help!

Hi , its the first time i post here(sorry for my english, i’m spanish speaker), i need some help , i created a custom trunk via freepbx with custom dial string : Local/[email protected]
and in extensions_custom i have this:

[timeoutx1]

exten => _X.,1,Dial(ZAP/g0/${EXTEN},30,TtL(20000))
exten => _X.,2,Answer

option L it’s the timer in ms

but past the 20 s the call dont hangup, but in the extensions module if i change in any extension the context from-internl to timeoutx1 it work perfectly, so i dont know what’s the problem.