Flagging this question as it appears marked as answered but I don't see a public reply, can you verify how resubscribes work?
Re-subscribe functionality — Blackbaud Community
Hello @PSG Claudia In the integration between Raiser’s Edge NXT and Constant Contact, a "global opt-out" is easy to achieve, but a resubscribe requires an explicit action from the supporter. Because of strict anti-spam regulations (like CAN-SPAM), you cannot simply uncheck a box in RE NXT to start emailing them again; the supporter must "opt back in" through one of these methods.
This is the most seamless way for someone to rejoin your list:
If a donor contacts you directly asking to be added back, you can trigger a one-time invitation:
Once the supporter confirms their resubscription in Constant Contact: