Plugin version: 1.4.13
Google webmaster page shows below message for sitemap: http://crunchify.com/post_tag-sitemap3.xml (NOTE: other sitemap links work fine)
********************************
Errors
Unsupported file format
Your Sitemap does not appear to be in a supported format. Please ensure it meets our Sitemap guidelines and resubmit.
********************************
Quick observation:
- When I keep max entries/sitemap to 500, above error message appeared for tag-sitemap3 and tag-sitemap4.
- When I keep max entries/sitemap to blank (1000), above error message appeared for tag-sitemap3.
==> tag-sitemap1,2 generates fine (if you have too many tags) but issue start after that, i.e. for 3, 4..
Other than this everything works just fine.