Here are some similar answers that have been posted that should be able to help you out:
[
Change email status when create new contact via API?
community.keap.com
](Change email status when create new contact via API?)
[
How to make contact’s Email status Marketable by REST API? Or manually from CRM?
community.keap.com
If someone is marked as ‘non-marketable’ or ‘opted-out’ you are not able to mark them as ‘marketable’ or ‘opted-in’ via the API. This has been disabled to avoid abuse. The only way to get them opted in again is to send the email confirmation and have them opt-in, or to have them complete a web form (which opts them in).
Thanks,
Jeff