emagencia on "[Plugin: MailPoet Newsletters] Subscribers become "unsubscribed" without asking for"

More and more of my subscribers become "unsubscribed", while I am sure they have not made the step to unsubscribe.
Where does the problem come from ?

Thanks

https://wordpress.org/plugins/wysija-newsletters/

We've seen this odd behavior happening with some other users as well. We haven't found the exact cause yet, but it seems to come from the sending method. Which sending method are you using? (Settings page > Send with tab)

I use Sengrid