Oops, it looks like you are trying to call a child command before running a parent command.

You wrote code that looks like this:

cy.find("main.overlay:nth-child(1) > div.widget.position-relative:nth-child(7) > div.widget__overlay.position-relative > form.widget__content > button.btn.btn-submit.btn-primary.mt-4.btn-bottom")

A child command must be chained after a parent because it operates on a previous subject.

For example - if we were issuing the child command click...

cy
  .get('button') // parent command must come first
  .click()       // then child command comes second