TYPE FORM PROBLEM

Hello. I sent an email marketing yesterday to 127 people. I wanted to ask them a few questions so I used typeform. I made a lot of trial before sending the e-mail to be sure that the URL of typeform works on my email marketing. But unfortunately, people who received the email  marketing can’t answer to the typeform because it’s written that the form is closed. I don’t undestrand why. Please help me!