On 19th September 2015, we changed the server tmc.openvehicles.com to a new IP address - 18.104.22.168. Please make sure you are using this as your Server IP parameter.
The dns record for tmc.openvehicles.com has been changed already, but may take a few hours to propagate.
You can reconfigure your car, from your registered phone by sms message "SERVER 22.214.171.124".
Cars connecting to the old server address will be auto-migrated to the new server, where possible.