Comment on SEO AdSense WordPress Theme by SEO Dave.
Or editing a WordPress Page or Posts under your WordPress Dashboard and copying and pasting the AdSense code into were the post content goes?
The former (editing the right PHP file) will work if you know what you are doing PHP wise. The latter depends on how you do it, for example if you do this it fails:
Edit a Post.
Click “Text” mode.
Paste in your AdSense Responsive code.
Click “Visual” mode.
WordPress messes up the Responsive AdSense code. Not checked what it does with the legacy AdSense code, the old AdSense code and the new responsive code are different formats and wouldn’t be surprised if Google treats them differently.
I generally don’t add code very often to Posts, but when I do I always keep the post in Text mode and never go to Visual mode because of the above.
If it’s not the above you’ll need to explain in full detail what you are doing.
You can view source in a browser like FireFox and check if the AdSense code has changed after saving the post. If it has you know it’s WordPress changing the code.