I have a weird problem where some email addresses are automatically getting added to my Global Unsubscribes after each API send to that address.
The initial email gets sent and delivered, but then the receiving address is automatically added to the group, and any subsequent API sends will cause the email to get dropped immediately. I have to manually remove the addresses every time.
Does anyone have any ideas what could be causing this?
I had the same issue, it seems like some spam filters "click" all the links that are in emails. I also contacted sendgrid support and they confirmed that this might be the case and there is nothing they can do about it.
Unfortunately the only solution I could come up with is a two step unsubscribe, that you have to implement yourself. Creating unsubscribe links that redirect you to your own server, where you add a confirmation step.