Cannot call toll free numbers or 3-digit numbers using voip.ms with softphone apps

With my LAN phone plugged into a Grandstream HT701 ATA, I am able to call toll-free numbers and three digit numbers like 311 and 211 with my voip.ms account. When I call 3-digit numbers with my Android phone using cSipSimple or Zoiper, I get a voice message that says "The number you have dialed has not been recognized". When I call toll free numbers with those apps I get a voice message that says "41611" with cSipSimple and "41613" with Zoiper, followed by "We're sorry because of technical difficulties we are unable to route your call". I am able to dial regular 10 digit phone numbers without any problems. Is there a way to fix this or is this just a limitation of softphone apps? I also don't get the above errors with Android's native SIP client but I would like to use cSipSimple for it's features e.g. call recording.