I assume you are accessing the Online Gallery - we have seen this issue a few times recently - the problem is with the Online Design Gallery servers at Magix and it appears to be intermittent.
Try again later, if the problem persists, send an email to Magix at infoservice@magix.net quoting the error message.
When you have connection again, to avoid having to go to the Online Gallery, you can download the entire Online Gallery contents to your computer it will then appear as the Local Designs Gallery - see The Local Designs Gallery section in the PDF manual, pages 29 -31 for Web Designer 19, available under Help in the program..