Specifically, the SREs were granted for 180 days and expired on May 2, 2019.
After their expiry, the government of the US announced that the SREs will not be renewed, which is amongst their policies on bringing maximum pressure to bear against Iran, in order to negatively affect Iranian oil exports and bring them to zero.
Moreover, on May 20, Brian Hook - the US Special Representative for Iran - warned that the US will sanction any country that buys oil from Iran. This includes the purchase of oil by the eight countries that were previously granted SREs.
In the meantime, the US deployed the USS Abraham Lincoln Carrier Strike Group and a bomber task force to the US Central Command region, as a response to a number of troubling and escalatory indications and warnings to Iran.