Error: "Unable to connect to the Notes Migrator for SharePoint Import Service at 'http://:8888/Im (4270571)

The following error is returned  during migration job execution or while testing connection:

"System.InvalidOperationException: Unable to connect to the Notes Migrator for SharePoint Import Service at 'http://:8888/ImportSession.svc' due to the following error: 'Invalid URI: The hostname could not be parsed.'
at Quest.NSP.SharePoint.SharePointRemoteLoad.WriteSharePointList(TransferJob job, IDataReader reader, XmlDocument databaseInfo, ImportServiceConnectionSettings importServiceConnectionSettings, ClientCredentials credentials, IFeedback progress, EventSeverity minLogSeverity)
at Quest.NSP.Migrator.ProgressForm.RunJob(String jobName, TransferJob job, Options options, MigratorLicense license)"