sends email but returns error

This is most likely due to a Javascript conflict with either your current WordPress theme or one of the other plugins you are using – see Solving CF7 Javascript Conflicts.

I tested it with the standard 2013 WordPress theme and the only plugins used were Easy WP SMTP and Really Simple CAPTCHA, which were required for my contact form.

Include a link to your CF7 form if possible.

Thanks, but I already switched to using the Fast Secure Contact Form, which appears to work just fine.

If Fast Secure Contact Form uses no Javascript that could resolve a Javascript conflict.

Remember that a problem in one script can cause issues in another. For example, some jQuery errors can stop jQuery processing any more script, which can make the culprit hard to find. A jQuery error in one of your plugins or your themes javascript files can stop jQuery processing before it gets to the CF7 script.

If this resolves your question, it helps others contributing here, if you can flag your post as [resolved]

Understood, and thanks for the help. I spent about an hour debugging the CF7 code and it seems more like a server side problem than a client problem, since the data gets sent to the server and an the error I mentioned above gets returned back to the client. Unfortunately, since I could not get CF7 to work with all other plugins deactivated and with the standard Twenty Thirteen them that comes with WP, then I simply had to abandon using it.

Hi, I know you switch to other solution. But for those who might come across this problem, it can simply because you activate the ‘debug option’ in Easy SMTP.

So if that is set, the server return some extra information like
Server …. (start with ‘S’)
before the actual json
{“message”:”Your message has been sent successfully”}

And the js cannot parse the response in this case. That’s why there is no message display. So remember to switch off the debug option