I checked your sitemap and I see no errors and I can view the sitemap just fine – view-source:http://www.cmelastablas.com/sitemap.xml
Similar errors on a sitemap. Just activated
This page contains the following errors:
warning on line 2 at column 216: xmlns: URI //www.sitemaps.org/schemas/sitemap/0.9 is not absolute
error on line 382 at column 67: EntityRef: expecting ';'
Below is a rendering of the page up to the first error.
I don’t see that error but I do see this error:
This page contains the following errors:
error on line 2 at column 6: XML declaration allowed only at the start of the document
Below is a rendering of the page up to the first error.
The cause of that error is a blank space before the opening PHP tags or after the closing PHP tags in one of the files on your site. This is a well known issue with XML code, if an invalid blank space is detected in a PHP file then you will get this error. You’ll need to go through all your PHP files to try to find the invalid space. I recommend starting with the PHP files in your theme.