TypeError: Cannot read property 'nickname' of null

[benjamin-dk]

2017-06-08T16:43:42.113Z - info: Regular user disconnected. 0386830b-5b8f-4534-93bb-921041a75aa6
2017-06-08T16:43:42.114Z - info: User logout: No valid reference to client.
2017-06-08T16:43:42.114Z - info: User logout: Chat duration (minutes):  9
stream.js:74
      throw er; // Unhandled stream error in pipe.
      ^

TypeError: Cannot read property 'nickname' of null
    at Client.<anonymous> (/home/ch-group/domains/ch-group-node.curachat.com/opeka/nodejs/lib/opeka.js:691:33)
    at methods.(anonymous function) (/home/ch-group/domains/ch-group-node.curachat.com/opeka/nodejs/lib/groups.js:184:49)
    at Proto.apply (/home/ubuntu/.nvm/versions/node/v6.6.0/lib/node_modules/dnode/node_modules/dnode-protocol/index.js:123:13)
    at Proto.handle (/home/ubuntu/.nvm/versions/node/v6.6.0/lib/node_modules/dnode/node_modules/dnode-protocol/index.js:99:19)
    at D.dnode.handle (/home/ubuntu/.nvm/versions/node/v6.6.0/lib/node_modules/dnode/lib/dnode.js:140:21)
    at D.dnode.write (/home/ubuntu/.nvm/versions/node/v6.6.0/lib/node_modules/dnode/lib/dnode.js:128:22)
    at SockJSConnection.ondata (stream.js:31:26)
    at emitOne (events.js:96:13)
    at SockJSConnection.emit (events.js:188:7)
    at Session.didMessage (/home/ubuntu/.nvm/versions/node/v6.6.0/lib/node_modules/shoe/node_modules/sockjs/lib/transport.js:220:25)
error: Forever detected script exited with code: 1
error: Script restart attempt #1
2017-06-08T16:44:06.262Z - info: Connecting to database...