Accent in the conjugation of décevoir?

I was doing a quiz, but I kept getting one nearly correct answer. It was the verb décevoir (to disappoint). On the quiz, the question’s subject was they (ils/elles) so I typed déçoivent, but Kwiziq’s correct answer was deçoivent with no accent on the e. 

Am I doing something wrong? Did I miss something or is this a mistake? 

Thanks,

Sarah