To resolve this issue go to:
yoursite.com/wp-content/plugins/mailchimp-widget/lib/ns_widget_mailchimp.class.php
onb line 249 there is:
$this->hash_mailing_list_id($this->number) == $_COOKIE[$this->id_base . '-' . $this->number] || false == $this->ns_mc_plugin->get_mcapi()
Just delete this and write in the brackets false.
This should resolve the issue and load the widget every time.
FYI, I designed it to disappear after signing up because it seemed odd to have it there all the time, even after users have signed up for the list. Another option, if you’re testing, would be to clear your cookies… if you do, voila! it’ll be back again 🙂
Happy blogging!
James