Event ID 53106 "Unable to Save Message" occurs in Skype for Business Server 2015 Persistent Chat Server

When you configure the Persistent Chat Compliance service in a Microsoft Skype for Business Server 2015 multiple-server pool environment, the following event is logged on the Skype for Business Server 2015, Persistent Chat server.

Time: Date/Time
ID: 53106
Level: Error
Source: LS Persistent Chat Compliance Server
Machine: SERVER Name
Message: Unable to save message Date/Time PART ma-chan://domain.com/XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX X XXXXX to database due to exception:
CmdID: XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX The server could not restore db connection within the allowed time (00:10:00) using connection string: Data Source=SERVER.domain.com\PCHATDB; 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 of a race condition when you update tblComplianceParticipant table entries.

To fix this issue, install the May 2017 cumulative update 6.0.9319.281 for Skype for Business Server 2015, Persistent Chat Server.