There are two XSS issues:

Example A:

1. Create a new form.
2. Go to settings and then to custom messages.
3. In form sent replace message sent with <script>alert(1)</script> payload.

Example B:

1. Go to add field and then add email.
2. In label change your email to <script>alert(1)</script> payload
3. Now return to your submissions and click on the recent submission you made to see the XSS.