Unexpected crash from time to time.

Hi guys, recently my server started to crashing from time to time, with strange error in logs:

Code:

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2015-09-16 13:05:58.091056|ERROR  |              |  | TS3ANetwork::ResolveHostName failed error: -3 (Temporary failure in name resolution) 11
2015-09-16 17:36:00.032475|ERROR  |              |  | TS3ANetwork::ResolveHostName failed error: -3 (Temporary failure in name resolution) 11
2015-09-18 12:26:10.852281|ERROR  |              |  | TS3ANetwork::ResolveHostName failed error: -3 (Temporary failure in name resolution) 11

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Do you know what may cause this?
Thanks in advance.

Unexpected crash from time to time.