Hi @anawalmart ,
Thanks for your message.
Sorry to hear you couldn’t get the plugin working for you. When I checked Optin Cat on my own site with Mailchimp, it works for me.
We have this guide here for troubleshooting Optin Cat issues – https://fatcatapps.com/knowledge-base/test-email-integrations/
I would recommend trouble shooting the above issues and checking to see if that solves the issue.
You can also try sending us a link to your optin form and we can try trouble shooting from our side.
Feel free to reach out to us again if you have any issues.
All the best.
Another part of your site you can check is if your site has any caching or optimization plugins. Sometimes these can prevent the nonce from working properly with the API.
In that case, you can clear your cache from your site and set your plugin to ignore Optin Cat from being cached.