Gallery page image to attachment page for seo

Hi, created a gallery page here http://www.paralleltime.com/gallery/. When i click on the image it try to open but never reach the attachment page.
But, the attachment page is working fine http://www.paralleltime.com/gallery/sen-dar-character-sketch/

I check the permalinks they it looks fine. Previous i have used the jetpack plugin and to try to fix the issue i removed it but its still not working. Please suggest.
Thank You