Thanks for using Caldera Forms, we really appreciate it. I’m sorry to hear your emails aren’t working as expected. It makes sense that the problem would particularly persist with Gmail, as antispam is one of Gmail’s key differentiators.
Email deliverability is a well-known problem among WordPress form plugins, as you can see here. The ability of Caldera Forms Free and other contact form plugins to send emails is dependent on WordPress’ mailer functionality, which is not terribly reliable across all server configurations.
Personally, I never rely on my WordPress host for sending emails from the form mailer, or the autoresponder processors. The main feature of our paid version of Caldera Forms is to address email deliverability. This is probably the fastest solution to your problem. You can see more information here: https://calderaforms.com/pro/.
