Hi,
I've been looking for this all over the place but I can't seem to find anything helpful.
I'm running two sites in a multisite install. Actually three, but one is more of a dummy site I use to test for stuff.
Main site: http://www.dreadfulgate.de/wordpress/
Sub-site: http://www.dreadfulgate.de/wordpress/eng/
Recently, I changed the theme from Comicpress to Mantra with the Comic Easel plugin. Since then, when I try to link to the sub-site from Facebook or Google+, it just doesn't work. Facebook doesn't seem to even acknowledge that I'm entering a url, and Google+ gives me the error message: "Could not load website."
I checked both sites with the w3 validator, and it gave me an error 500 note for the child site. (But I have no problems accessing the site, nor the admin pages.)
Everything works fine on my main site and the dummy site, which use the same theme and plugins, so it can't really be them. I deactivated them anyway and checked the child site's child theme with the dummy site. I switched to the main site's child theme, too, no change.
I'm suspecting it's a .htaccess thing. But I'm not sure about that since any change there would probably affect both the dummy site and the child site, and only one of them is having troubles.
Any pointers will be appreciated.
Thanks in advance!