There are several possibilities. It would be easier to find the problem if someone could look at the local Call History to see what digits have dialled by the Auto Attendant and which sp they have been routed to. Call History is only available via the local web page - dial ***1 to find the ip address, "admin" and "admin" will get you past the password etc.
The Auto Attendant has its own Primary Line, Digit Map, and OutboundCallRoute, so it is possible that these are not set the same as for the Phone Port. This might result in the Auto Attendant trying to dial numbers that are not valid for a particular service provider. However, this is unlikely if you have not changed the defaults, then the Primary Line is most likely sp1 and the digit maps should work for most service providers.
If there is someone at the local site, then they can dial **0 from the Phone Port which will connect them to the Auto Attendant and then select Option 2 and try to dial from there. If that works and you have problems using the Auto Attendant remotely, then the problem may be the way in which you are sending the DTMF tones after you have connected to the Auto Attendant. If you are dialling from your US OBi, then you can try different methods of sending DTMF. Is the problem the same if you dial to the Philippines OBi via a landline or cell phone or via the local OBi?
Easiest tests are to try AA locally see if that works first, then think about possible remote problems.