United made a failed attempt for the Morocco international in the final days of the January market.
Amrabat's representative, Mohamed Sinouh, told Kora Plus: "For now we don't have any offer for the summer, but now at least Fiorentina is willing to listen. A promise they made when the president rejected all the offers in winter.
"We received many offers during the January transfer window, including one from Manchester United, but an agreement cannot be reached."
Amrabat has a deal with Fiorentina to 2024.