Event ID 53106 "Unable to save message" is logged in Lync Server 2013 Persistent Chat Compliance Server

Consider the following scenario:

• The Persistent Chat Compliance service is enabled in a Microsoft Lync Server 2013 environment.
• Users are moved between Persistent Chat servers, or rejoin a chat room.

In this scenario, you may receive the following event frequently in a day. This indicates a failure of delivering the compliance data to the mg comp database:

Time: Date/Time
ID: 53106
Level: Error
Source: LS Persistent Chat Compliance Server
Machine: ServerName
Message: Unable to save message Date/Time PART ma-chan://contoso.com/ID to database due to exception:
CmdID: CmdID The server could not restore db connection within the allowed time (00:10:00) using connection string: Data Source=sql.contoso.com\RTC;Initial Catalog=mgccomp;Integrated Security=SSPI. at
at Microsoft.Rtc.Internal.Chat.Server.ServerCommon.Database.DbCommand.executeUntilSuccessOrTimeout[TR](Fun`2 executeDelegate, RetryInfo retryInfo)
at Microsoft.Rtc.Internal.Chat.Server.ServerCommon.Database.DbCommand.executeImp[TR](Fun`2 executeDelegate, Int32 retryTimeoutInMs)
at Microsoft.Rtc.Internal.Chat.Server.ServerCommon.Database.DbCommand.ExecuteNonQuery(Int32 retryTimeoutInMs)
at Microsoft.Rtc.Internal.Chat.Server.Compliance.ComplianceDataAccess.Save(RawComplianceData data)
at Microsoft.Rtc.Internal.Chat.Server.Compliance.ComplianceServer.Save(RawComplianceData data).

This issue occurs because users are connected to a different server when they move between Persistent Chat servers or rejoin a chat room. But the compliance service isn't tracking the join entry. This causes the server to write errors.

To fix this issue, install the July 2017 cumulative update 5.0.8308.992 for the Lync Server 2013, Persistent Chat.