I need your help. I am using 3Cx with 3digits extensions in the office but we are not able to contact public services like ''911'' or others that also use 3digits free phone contact. Can somebody tell how to deal with this problem?
You haven't provided enough information to make anything more than a guess, as to what your problem might be. I'm also not sure if it involves the Android App or not, you did post in that forum after all.
I would guess it's your outbound rules, or perhaps a dial plan in the sets.