I have an unwanted Google Tag Manager popping up on my company's website. We have lost access to the old tag manager (hence the new one).
Using Chrome Dev tools I am able to see the unwanted tag id as a source (http://www.googletagmanager.com/gtm.js?id=GTM-XXXXXX) along with the new correct tag. However, I am not able to work out where that script is coming from!
Is there anyway to work out what is injecting that script into our site?