When filling out the form on my website, users see an error message: “Data sending is impossible. Go to Site settings and enter a valid domain name from which form responses will be sent. Or else the data receiver is not connected to this form or was deleted. Data was sent from this domain.” Why?
Only one assigned domain (and all of its subdomains) can receive applications.
Go to Site settings → Forms → scroll down to General forms settings → set the Domain for data capture services → Save → re-publish all the pages.
Before reviewing the forms, refresh (reload) the page 2-3 times in a row.