Need Help! "Unable to determine your identity, therefore we are unable to process your request."

I am working on a solution (Automation) that allows people to approve a certain request (from the form). In the approval workflows I created, I am sending an automatic approval request to an email indicated in a cell. The recipient received the email request, but when opening the request (clicking the button in email), the message (see image) below shows.

Does this process of approval only applicable to individuals with Smartsheet account? Or can this be allowed to even without credentials?

Thank you.