We want to test demand for 5 potential new products by asking people to sign up to a newsletter form. Each of the 5 forms links through to a different mailing list in Campaigns. When testing these by filling in the form in the newsletter block to a variety of different email addresses, sometimes these email inboxes get the confirmation emails and sometimes not (we have checked spam/promotions/trash etc via webmail pages to avoid any Outlook rules). Sometimes Squarespace appears to send them later, sometimes not at all. Sometimes we get and click the confirmation email, and the subscriber isn't registered in the mailing list, sometimes they are.
Not sure if there are limits to how many newsletter forms you can have, how many emails can be sent to one recipient in a day, or whether we have some kind of quota or maximum we're using up trying to test whether this works before we launch.
We have had to delay the entire site going live as this is so unpredictable.
We haven't moved the domain from our old provider to squarespace yet so worst case appears to be that we go live, add recaptcha, drop the confirmation emails, then test again.