System.InvalidOperationException error on website

Yesterday for several hours I was getting errors on my website like the one below - 3-4 per minute.  The website also periodically failed to render with "Too many automatic redirections were attempted" error.  Our hosting provider (PowerDNN) runs some optimizations every night and the site seems to be OK today and we're not getting the errors any more.  Any idea what could have caused this?  Or what we can do to fix it in the future?

 

AssemblyVersion: 5.4.4
PortalID: -1
PortalName:
UserID: -1
UserName:
ActiveTabID: -1
ActiveTabName:
RawURL:
AbsoluteURL:
AbsoluteURLReferrer:
UserAgent:
DefaultDataProvider: DotNetNuke.Data.SqlDataProvider, DotNetNuke.SqlDataProvider
ExceptionGUID: e04e326d-0236-4cdd-aa4c-9a356a069f62
InnerException: This SqlTransaction has completed; it is no longer usable.
FileName:
FileLineNumber: 0
FileColumnNumber: 0
Method: System.Data.SqlClient.SqlTransaction.ZombieCheck
StackTrace:
Message: System.InvalidOperationException: This SqlTransaction has completed; it is no longer usable. at System.Data.SqlClient.SqlTransaction.ZombieCheck() at System.Data.SqlClient.SqlTransaction.Rollback() at SD.LLBLGen.Pro.ORMSupportClasses.DataAccessAdapterBase.Rollback() at SD.LLBLGen.Pro.ORMSupportClasses.UnitOfWork2.Commit(IDataAccessAdapter adapterToUse, Boolean autoCommit) at Aricie.DNN.Services.Url.FriendlyUrl.Data.FupPersistenceJob.Commit(DataAccessAdapterBase objAdapter)
Source:
Server Name: M66R38

Thanks,

Gigi Payne