The OnSip click to call plugin for your Firefox or Google Chrome browser is configured with your sip address, but when you click on highlighted numbers to call, nothing happens.
Advanced Note: If using Wireshark or other packet capture software you would notice the outbound request to the OnSIP API is being sent successfully, however no response ever arrives.
More than likely the SIP phone you are expecting the call to ring on is behind a router or other network device with a SIP NAT helper. You should disable any SIP NAT helpers (such as those in Tomato or DD-WRT) unless you have a specific need to have it enabled. SIP NAT helpers are typically not needed when UDP timeouts and session keep alive intervals are configured properly.