We are using SharePoint 2013 On-premise. User want to change the theme of their "My site" or their "blog". In the browser he type in the URL like this:
http://mysite.domain.com/personal/testuser//_layouts/15/designgallery.aspx
It go to Design Gallery. After he pick a theme and click "try it out", page show up with
"403 FORBIDDEN" error.
Is it our configuration settings problem or are SharePoint users are not allowed to change blog's theme?