Is IE a supported browser? If so, https://github.com/validatorjs/validator.js/blob/master/validator.js#L429 has a call to String.prototype.includes(), which fails in IE as it is not available on that browser.

A polyfill is available at https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/includes