Post Preview does not work

Hi,

I have a lot of WPMU Blogs and they all work fine. But today I noticed, that the Post Preview will not work with activated WPMU Domain Mapping Plugin. If I deactivate the Plugin, it works just fine.

When I push the button “Preview” it will open a new tab with the url of the post and appended “?preview=true”.

Can you please fix the problem?

Thanks a lot.

Best regards.