Are your Contact Form 7 submissions not working fine? Is the ‘Thank You’ success message flashing for a second and disappearing? The problem might be in the on_sent_ok hook.
The standard recommendation on the Contact Form 7 website is to use the following code.
on_sent_ok: "_gaq.push(['_trackEvent', 'Contact Form', 'Submit']);"
on_sent_ok: "ga('send', 'event', 'Contact Form', 'Submit');"
Now, if you are using Yoast’s WordPress Google Analytics plugin, you will have to change the trigger to the following:
on_sent_ok: "__gaTracker('send', 'event', 'Contact Form', 'Submit');"
I do not know why, but Yoast has decided to use ‘__gaTracker’ instead of ‘ga’.