https://www.treasury.gov/resource-center/sanctions/programs/...
https://www.treasury.gov/resource-center/faqs/Sanctions/Page...
630. Is the provision or delivery of goods or services to an Iranian counterparty after November 4, 2018 allowed?
The wind-down period has ended and the United States intends to fully enforce the sanctions that have come back into effect. The provision or delivery of goods or services and/or the extension of additional loans or credits to an Iranian counterparty after November 4, 2018 — even pursuant to written contracts or written agreements entered into prior to May 8, 2018 — may result in the imposition of U.S. sanctions unless such activities are exempt from regulation, authorized by OFAC, or otherwise not sanctionable.