If a field is not required and typeError is specified, on not entering anything also, it gives an error(typeError)

[vishal-gits]

I am using validation for postalcode in a input box.

phone: yup
.number()
.max(9)
.typeError("Provide in postalcode number format"),

When typeError() is given to phone(which is not specified required), and when nothing is entered for phone, then also it attaches a typeError to it. Ideally if nothing is entered and it is not specified "required", it should not give an error.