I'm receiving this error 
AssemblyVersion: 5.6.1
PortalID: -1
PortalName:
UserID: -1
UserName:
ActiveTabID: -1
ActiveTabName:
RawURL:
AbsoluteURL:
AbsoluteURLReferrer:
UserAgent:
DefaultDataProvider: DotNetNuke.Data.SqlDataProvider, DotNetNuke.SqlDataProvider
ExceptionGUID: 14f8a9c2-6dc6-43fa-894e-08bd911140d7
InnerException: FriendlyName
FileName:
FileLineNumber: 0
FileColumnNumber: 0
Method: System.Data.ProviderBase.FieldNameLookup.GetOrdinal
StackTrace:
Message: System.IndexOutOfRangeException: FriendlyName at System.Data.ProviderBase.FieldNameLookup.GetOrdinal(String fieldName) at System.Data.SqlClient.SqlDataReader.GetOrdinal(String name) at System.Data.SqlClient.SqlDataReader.get_Item(String name) at DotNetNuke.Services.Scheduling.ScheduleItem.FillInternal(IDataReader dr) at DotNetNuke.Common.Utilities.CBO.FillObjectFromReader(Object objObject, IDataReader dr)
Source:
Server Name:

I tried fixing this issue by upgrading/Repairing HTML Module, unable to fix it.