Everything works except outbound calls

[color=#000000]The PBX has been running for several years. SIP is used except for the actual trunking which is analog lines broken out from a T1 by an Adtran connected to a TDM400P with 4 FXO cards/ports. One day all worked. The next everything except external outbound calls. Any ideas? One post mentioned a license. I did not build this system. Is there a license?[/color]