Step 1: Go to AMP for WP Plugin under WordPress
Step 2: Click on Advance settings and then scroll down to Enter HTML in the Head as shown
Step 3: Remove any other scripts other than AMP script that’s already available and once it is fixed. You can test your page via Google’s AMP Test page to validate your fix. If the test fails keep looking whether there are any other scripts that are being inserted in the AMP page.