Most likely it's due to not establishing a proper connection to whatever server your connecting to. Could either be
A) Mismatching client/server version. Simply put, your vc-mp version doesn't match the version of the server you are trying to connect too. (I think, not sure if it displays an output on the client if there is a problem like that)
B) The system you are on is blocking gta-vc.exe from gaining access to the Internet e.g a Firewall rule on Windows Firewall/Anti-Virus software on the machine your using. Or it could be that the router on your network has specific rules to block port information related to vc-mp from going in and out of your network.
C) Lastly it could just be something silly like a mistyped IP address or connecting to a server that doesn't exist. For example sometimes when copying and pasting an IP address to the "Add Server" on the favourites menu it will leave a blank space at the end of the IP address which the browser recognises and becomes something totally different. Another really silly case of this would be if a friend set up a server and told you
"Come join my server at 192.168.2.1:5192" Which is a local network private IP address so you wouldn't get anywhere with that.
