ContributionsMost RecentMost LikesSolutionsInvalid filing period Hi, I have been trying to file my G.S.T Return for Dec 2019 and Jan 2020 two monthly filings, has been switched to 6 monthly filings from Feb 2020. When I do try to file the two monthly one ending Jan 2020 it comes up with the below message, I have cleared the cache and others in settings. I have always used Google Chrome. Your GST return could not be pre-filled because Inland Revenue returned the following error(s): IRD response code 104, Invalid filing period. Thanks Jeff. Solved