same issue here. The only weird thing is it was working just fine, then stopped. I can't figure out what broke it.
- sidebar widget form doesn't add emails to database.
- sidebar widget form doesn't give any errors.
- bulk invite from dashboard is adding emails to database but not emailing the invite.
- invite restriction is still working, tested by trying to sign in with an uninvited email.
Here's a list of fixes that have been tried with no change:
turned cloudflare off.
disabled minify on w3totalcache.
tested wp email sending with http://www.stillbreathing.co.uk/wordpress/check-email/ Works fine.
added wp_load above where php adds the emails to database. require_once('/wp-load.php');
took out the action on the form completely - per http://wordpress.stackexchange.com/questions/14347/a-form-in-a-custom-widget
added a php widget using Executable PHP widget with a do shortcode inviteform, no change.
tried the shortcode inviteform on a page also, same thing.
tried get_permalink() in the action part of the form per the comments on http://wordpress.stackexchange.com/questions/14347/a-form-in-a-custom-widget
Repaired database with WP-DBManager