Its a big file, but the below seems to be a common theme.
---- Stack Trace ----
[6/27/2018 2:44:19 PM] (Inner Exception)
Date and Time: 6/27/2018 2:44:19 PM
Machine Name: Computer-Name
Machine IP: fe80::ac90:a8de:c3b5:2196%26
Machine OS: Microsoft Windows NT 6.1.7601 Service Pack 1
Application Domain: openHistorian.exe
Assembly Codebase: C:/Program Files/openHistorian/openHistorian.exe
Assembly Full Name: openHistorian, Version=2.5.6.0, Culture=neutral, PublicKeyToken=null
Assembly Version: 2.5.6.0
Assembly Build Date: 6/1/2018 12:22:34 AM
.Net Runtime Version: 4.0.30319.42000
Exception Source: ModbusAdapters
Exception Type: System.NullReferenceException
Exception Message: Object reference not set to an instance of an object.
Exception Target Site: AttemptConnection
---- Stack Trace ----
ModbusAdapters.ModbusPoller.AttemptConnection()
openHistorian.exe: N 00617
GSF.TimeSeries.Adapters.InputAdapterBase.AttemptConnectionOperation()
openHistorian.exe: N 00250
(Outer Exception)
Date and Time: 6/27/2018 2:44:19 PM
Machine Name: Computer-Name
Machine IP: fe80::ac90:a8de:c3b5:2196%26
Machine OS: Microsoft Windows NT 6.1.7601 Service Pack 1
Application Domain: openHistorian.exe
Assembly Codebase: C:/Program Files/openHistorian/openHistorian.exe
Assembly Full Name: openHistorian, Version=2.5.6.0, Culture=neutral, PublicKeyToken=null
Assembly Version: 2.5.6.0
Assembly Build Date: 6/1/2018 12:22:34 AM
.Net Runtime Version: 4.0.30319.42000
Exception Source:
Exception Type: System.InvalidOperationException
Exception Message: Connection attempt failed: Object reference not set to an instance of an object.