Help! 403 access forbidden on page after upgrading to 3.0.5

Hi,

after upgrading a single page on my site is giving me problems with the “403 access forbidden” error message. The page I am talking about is here: https://www.tigerbeat6.com/artists/
however, I can still access subpages of it with the permalinks, i.e. https://www.tigerbeat6.com/artists/cex

I can’t figure out for the life of me what the problem is, since it is just this single page. I appreciate any (quick) help!

Thanks in advance