The browser security error occurs for several reasons. If your browser says that the web page where your form is hosted is unsecure, check if SSL encryption is activated for your form. Go to the section Get Code & Publish and, at page top, check the option Secured SSL if it is unchecked.
If the browser security error persists, make sure that the images in your form have a secured URL. Secured URLs start with https, instead of http.
If your images are not hosted on a secured website, then upload them to the 123ContactForm website. Add an Image field to your form, upload the image from your computer and then retrieve its secure URL from the form code. Delete the Image field, create a new one and – instead of uploading the image – paste the secure URL generated by our platform.