Check your validationSchema. I ran into this problem and found that my validator was returning something that signaled to Formik the form was invalid, but no other warnings or messages were coming up. It just wouldn’t submit.
Replace that prop with validator={() => ({})} i.e. just an empty object being returned. That should pass validation and trigger your onSubmit. You can restore your functionality from there.
<Formik
initialValues={{
email: ""
}}
onSubmit={() => { console.log("submit!"); }}
validator={() => ({})}
>
{/* */}
</Formik>