Dial plan problem

Hello

in extensions.conf i have:
[numberplan-custom-1]
plancomment = DialPlan1
include = default
exten => _##12X.,1,Dial(IAX2/trunk_t2/${EXTEN:4})
exten => _X.,2,Dial(IAX2/trunk_t2/${EXTEN})

When i call using ##12 prefix i connect thru trunk_2 and everything works fine.
When i call directly i can not connect and receive error:

[Mar 16 13:18:37] NOTICE[17283]: chan_iax2.c:7146 socket_process: Rejected connect attempt from 192.168.100.165, request ‘0801300800@numberplan-custom-1’ does not exist

Why ?
Thanx

Because your _X. extension does not have priority 1.