RemoteToPC traverses most firewalls, but some firewall software actively stops activity for applications automatically because it has been configured to. Also, for network administrators that block all outbound firewall traffic, you’ll need to open outbound TCP ports for the host and join side computers: 5222, 5223, and 3478, as well as outbound UDP ports 3478, and 49152-65535. (Note: Monitoring uses outbound TCP port 5672 and 5671)

Try our connection test tool to see if anything on the system or network is blocking RemoteToPC: Connection Test