I have Mitel SX-50 install with 4 Lines. I started to have problem with outbound call at the motel in last 3 days now.
I get calls in from all the number when i call the motel from cell phone but can't make any calls from the motel on 3 lines.
At&t came and checked all the line they said the problem is with our system and all line are up.
I keep getting an alarm on the main display right after i try to make a call out.( When i dial 9 for outside line, no dial tone come). Get this 3 different messages...

" A 11 0073 NO TRUNK SEIZE ACK. 10/01"
" A 11 0074 NO TRUNK SEIZE ACK. 10/02"
" A 11 0075 NO TRUNK SEIZE ACK. 10/03"

When this 3 trunks get busy out i am able to get a dial tone and call out on trunk 76 which is the 4th line.

If you can help me it would be a grate help.