Thanks everyone for responding, I got it fixed.

Had that problem yesterday and it was simply that I added the code in the visual tab instead of the text tab.
I put mine in a side widget.
After correcting it, it was blank for about an hour. Then the ad's started showing up.
Doug

How did you add the verification code?

If you did it by editing your theme in Appearance > Editor, I'd delete it, as you'll have to redo it every time there's a theme update, as the code will get overwritten unless you have a child theme.

I recommend you install the Header & Footer plugin. https://wordpress.org/plugins/header-footer/ and then go to Settings > Header and Footer and insert it into the Head Section injection panel.

I'd also suggest using a plugin, either Ad Inserter https://wordpress.org/plugins/ad-inserter/ or WP Quads https://wordpress.org/plugins/quick-adsense-reloaded/ to manage your ads.

Nate has done some great training on Ad Inserter here: How To Use The Ad Inserter Plugin You might also want to consider Adsense Invalid Click Protector to stop click bombs. https://wordpress.org/plugins/ad-invalid-click-protector/

This normally happens if your code is not correct, somewhere you have not closed the code correctly. Did you do a copy paste of the code or type it in manually? Look it up, you might find the culprit. :))