Error in Date / Time Stamp

Error message from Google webmaster tools:

“An invalid date was found. Please fix the date or formatting before resubmitting.”

Can you send a link to the xml sitemap to Scott or myself to take at look at this?

I just checked again and I still see a yellow Explanation icon, however the error message is gone. Will check again in a few days.

I had the same issue with WP 3.9.2 and the italian locale (WP_LANG set to it_IT),
and the 1.0 plugin. My sitemap_index.xml looked like:

[...]
<sitemap>
<loc>https://[mywebsite.com]/pods_faq-sitemap.xml</loc>
<lastmod>2014-08-14 13:30:56</lastmod>
</sitemap>
[...]

The problem is the format of the date (not UTC).
I inserted this line in the classes/pods-seo-wpseo.php file, at line 228:
$lastmod = gmdate("Y-m-d\TH:i:s+00:00", strtotime($lastmod));

Then the error/warning on webmaster tools disappeared.

Michele

There is an error on line 155 of version 1.0, which I found to be causing the problem.

The code:

if ( !empty( $lastmod ) ) {
     date( 'c', strtotime( $lastmod ) );
}

Should be:

if ( !empty( $lastmod ) ) {
     $lastmod = date( 'c', strtotime( $lastmod ) );
}