I am attempting to create regular expression validation of one of my single line text field inputs that is supposed to be accpeting a phone number. Formatted as ###-###-####. 

I have tried:

as well as the following: ^d{3}{-]d{3}{-]d{4}? 

And seemingly correct input is still failing to validate

Used https://regexr.com/ to validate all of these so not sure what I am missing...