In telephony there isn't "partial failure", it is either success or failure.

If a fax fails in the middle and resends, for example, as far as the recipient is concerned, the fax failed. There is no way of the receiving device knowing whether the fax will be resent. It is like calling someone and then hanging up. The recipient doesn’t necessarily know if the caller will try again. But even if they do, the first call resulted in a failure.

A user may receive partial faxes, such as incomplete pages or pages that are cut off. These limitations are technology-based and industry-wide.