A ferry service that caters to Martha’s Vineyard and Nantucket was struck with a ransomware attack on Wednesday.

Massachusetts Steamship Authority announced that its customers are “unable to book or change vehicle reservations online or by phone,” and some may experience “delays,” though no threats “to the safety of vessel operations” have been noted as of noon. The company has requested patrons pay in cash as “the availability of credit card systems to process vehicle and passenger tickets, as well as parking lot fees, is limited.”