use of ga function in script

Hi there,

I am using mailchimp and would like to push a message when the signup button is validated (transmits a response). I added a script in the form using the ga(‘send’, …) function, which is not working. Does the ga function supposed to work with the GTM plugin ?
I am also using easy social share plugin to share/follow on social networks. This plugin uses the ga function to send to google analytics and it is not working either, so the problem may be linked.

Thank you in advance for your help.

https://wordpress.org/plugins/duracelltomi-google-tag-manager/