Hi!
Are you sure there is not a mistake in your VoIP.ms trunk outgoing settings (a bad account/subaccount name or a bad password, etc...)
I suggest you take a look at their wiki. See http://wiki.voip.ms/article/FreePBX_/_PBX_in_a_Flash
If all else fails, they are usually quite responsive (they are one of the VoIP providers I use...).
Good luck and have a nice day!
Nick