We cannot help to much if you have errors with Contact Form 7 or any other contact form plugins. Possible issues are not theme related but something deal with the server. We invite you to search on Google for similar issues and you can find that all the issue resolutions point to the server errors or configuration error of the plugin itself.
You can also activate the default WordPress theme (you don’t loose options and contents) and test a form, you’ll see that with the native WordPress theme you’ll have the same issue. Please note that in Uncode we only apply a few CSS rules to beautify the visual aspect of the form fields, nothing that can interfere with the functionalities.
We invite you to follow the Contact Form 7 official troubleshooting and contact your host:
NB: it’s possible that your host will tell that the problem is in the theme, so we invite you to test this on the default WordPress theme so they cannot tell the famous Contact Form 7 plugin doesn’t work cause the default WordPress theme.