Thank you for bringing this to our attention! We understand how important it is for a sign-up form to work so you can easily collect contact information. With that said, what WordPress and plugin version are you using? Do you have any other plugins installed? If you do have any other plugins running, a great troubleshooting step to take is to temporarily deactivating. Does this help resolve the issue? If so, what are the plugin names?
We have seen cases where users have this error message appear w hen the Constant Contact for WordPress is activated, and a user tries to edit one of their pages. In these experiences d eactivating the Constant Contact plugin, making necessary page edits and then reactivating the plugin has worked.
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