@penzygreen ,
Maybe the email is simply going to SPAM, and sometimes it doesn’t even show in the SPAM inbox. Please try these options to increase your deliverability rate.
1- First, you could simply try to change our “Email > Mail function“. You could have more luck with some of the options.
2- Try to set the “Emails > Activation Email > Email content” like this:
<p>Please <a href="%verification_url%" target="_blank">click here</a> to verify your email.</p>
3- You could install a plugin like Check & Log Email to log your emails. You’ll be able to check if the activation emails are being sent or not.
4- If they are being sent, probably they are arriving at SPAM. If that’s the case, you could try to send emails using SMTP by installing a plugin like Easy WP SMTP.
5- You may also need to contact your hosting provider and potentially configure DKIM or SPF records if they are going to spam.
Let me know if it helps.