"Debugging and troubleshooting", "List of MyChat Client errors", "Error #0276".
Error #0276: no connection with Asterisk server
The integration with Asterisk is on but there is no connection at the moment.
Usually, this issue occurs due to technical disconnection (temporary disconnection between MyChat Server and Asterisk server; access port to Asterisk is closed by firewall or anti-virus software), or Asterisk server is off or restarting.
Wait a bit until the connection restores. If it don't, and the Asterisk server works successfully — look for network issues (no physical connection, the traffic is filtered, or Asterisk network settings changed).