There are a few reasons why your welcome emails are not being sent to new subscribers.
1. Your subscriber has not confirmed their email (if you have double opt-in enabled).
Any subscribers with the “pending” status will not receive a welcome email until they confirm their email, which will change their status to “active.”
Consider turning on Smart Nudge to notify readers to confirm their email if they have not done so after two days.
You can do that by going to: Settings→ Publication → General (tab) → Double Opt-in (section)
2. Your welcome email was sent, but delivered to promotions/spam.
If you’re using a new custom domain, it can take time to “warm up” your domain and develop a positive reputation for it.
ISPs will notice a new stream of email from a new custom domain, and they might send these emails to promotions / spam. This will continue until you have built up a strong, positive reputation for your new domain.
To learn more about deliverability, check out some of our recent articles here.
3. They just need a moment.
Please allow up to 15-30 minutes for your welcome email to be sent to your subscribers. Especially during periods of high volume. they may not be sent immediately.