'There is a statute of limitations on refunds being claimed on amended returns. In general, if a refund is expected on an amended return, taxpayers must file the return within three years of the due date of the original return, or within two years after the date they paid the tax, whichever is later." I sounds like it possible that you missed the SOL on the 2014 amendment since the original due date was 4/15/15 and three years from that would have been April 2018.
https://apps.irs.gov/app/vita/conten...ed_returns.pdf

