From what I understand, there are some considerations for Network Administrators when it comes to things like RCS. It may not be a supported protocol on the routers your company uses behind its WiFi network. If this happens when you are at home, I would call your ISP and ask them if you can change a setting to allow for RCS. It also could be a matter of firewall ports. If I remember correctly I think I saw a friend of mine's RCS traffic when I ran a TCP dump of my own WiFi network at home. So if you know a thing or two about networking (or someone who does), and this is your network, good old fashioned TCP dumping may help find the problem. I am not sure what the traffic looks like though, if its HTTPS, TCP or UDP on the packet level. Still kind of new to RCS myself.