Problems with redirecting

Hi,

I work on the domain https://www.grofolkan.no. When I click on the logo in the header or choose English in the language menu, it redirects to an empty light box. I use the Divi theme from Elegant Themes and I have installed the NextGEN Pro plugin by Photocrati.

I was advised to check and edit the permalinks. Firstly, I checked to make sure the permalinks of the sites were correct. After I read the WP Codex on Using Permalinks, I thought there might be a glitch in the .htaccess file that WordPress generates. Therefore, I deleted the contents of the .htaccess file and re-created it. That did not change anything.