So, Trump claimed the closure and the attack "was a “foolish violation” of the ceasefire". However - that is not the case. The first and foremost item of the Iran-US MOU is the following: 1 — The United States of America and the Islamic Republic of Iran and their allies in the current war are signing this MOU to declare the immediate and permanent termination of military operations on all fronts, including in Lebanon…
It has to do with ships moving through the Oman side of the strait. Iran is unhappy with that, because the want to control all the movement through it.