This morning started seeing the error message as below , not sure what has changed . all of sudden all users are not able to search contacts just by typing the first Name or Last (But if we do EMail address which is also their SIP address works ok .) Suggestion
Address Book Server has encountered an unexpected exception.
Exception: Object reference not set to an instance of an object.
Exception Type: System.NullReferenceException
at Microsoft.Rtc.ABServer.ABServer.ReadContactsFromSqlAndWriteToOutput(NormalizeRuleSet normalizationRules, SqlConnection sqlConnection, List`1 sinks)
Cause: Internal Error
Contact Product Support Services.
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