I just called the end user who owns the fax. Thay said there fax did not pickup. But here is what I have on CLI. I have X out the last for for privacy reasons.

Attempting call on Zap/1/604327xxxx for s@callme:1 (Retry 1)
       > Channel Zap/1-1 was answered.
    -- Executing Wait("Zap/1-1", "3") in new stack
    -- Executing TxFAX("Zap/1-1", "|caller") in new stack
    -- Hungup 'Zap/1-1'






[callme]
exten => s,1,Wait(3)
exten => s,2,TxFax(${FAXFILE}|caller)


Channel: Zap/1/604xxxxxxx
MaxRetries: 1
RetryTime: 60
WaitTime: 40
Context: callme
Extension: s
Priority: 1

==============================================================

extentions.conf 

[callme]
exten => s,1,Wait(3)
exten => s,2,TxFax(${FAXFILE}|caller)


Channel: Zap/1/604xxxxxxx
 MaxRetries: 2
 RetryTime: 60
 WaitTime: 30
 Context: callme
 Extension: 800 
 Priority: 2 

What is the extnetion part for?