PrepMod, company behind Massachusetts COVID appointment booking website, apologizes after hours-long crash Updated Feb 19, 2021; The operator behind Massachusetts’ online appointment booking system issued an apology after the website crashed Thursday morning. “As the state’s biggest online appointment vendor, we deeply regret what happened [Thursday] in Massachusetts and are committed to ensuring this does not happen again,” Prep Mod said in a statement. “As public health servants and your partner, we are sorry for not meeting expectations. We accept full responsibility for the problem.” Thursday morning, when nearly a million more Massachusetts residents became eligible to receive the vaccine, the Massachusetts COVID vaccine appointment website was down for more than two hours.