Okay, you're using forwarding on the phone port (for all calls) instead of forwarding FPL's incoming calls (Voice Services-->SP-->Calling Features). My fault for not paying more attention to your second post.
What's happening is this: if your ATA rings for the number of rings specified by ForwardOnNoAnswerRingCount, your ATA attempts to forward the call to some OBihai device number via the Obitalk Network (pp). If the forwarded portion of the call fails, the incoming call is going to drop to FPL's voicemail system.
You originally had rings before voicemail set to 8. Your ATA rang 4 times, and it tried to forward the call. The forwarded portion of the call failed, and the incoming call, consequently, dropped to FPL's voicemail system. You might ((I've never tried forwarding from FPL to Obitalk Network) be able to observe what's happening during a live call, by logging into your ATA and navigating to Status-->Call Status (and refreshing the browser page). You can also check your call history.
Increasing ForwardOnNoAnswerRingCount above rings before voicemail (as defined by your FPL account) allows FPL's voicemail system to answer the call before your ATA tries to forward the call.
If you're not trying to forward unanswered calls, simply disable ForwardOnNoAnswer.
I won't be troubleshooting forwarded portions of calls failing from FPL's service to pp (Obitalk network). I keep Obitalk service disabled. However, forwarding calls with FPL using spx(1234567890), where x is the corresponding sp# you want to use, to dial a regular number works fine when X_Use302ToCallForward is disabled. The forwarded portion of the call is bridged, and the call won't automatically drop to FPL's voicemail system.