When you click on the +1 button above, I was getting a red exclaimation mark and I wasn't sure why.
Here are a few possible causes and solutions:
- The URL is not publicly available.
- In order for the button to function correctly, the page must be available without requiring authentication.
- The HTTP Response was not a 200.
- This was the cause of my troubles. I didn't realize that my page was returning a 404. I have since fixed the rewrite conditions in Apache to resolve this issue.
- Any redirecting of the user is not something that Google wants to +1.
I hope that helps!