Hi renatois,
It looks like you have the Title field which is a required field left blank upon submitting. Is this field displayed on the canvas? I am assuming that you are using a Custom SharePoint List form which is why this field is required. You may populate the Title field using the submit button and set its value with a unique value using a formula such as concat(username(), " - ", now()) -this formula concatenates the current user and the current time to make each submit unique. If this is not a SharePoint list form, then unchecking the "cannot be blank" at the fields properties should do the trick. Please let me know if this helps.
Regards,