Yeah it's gone for me too. They'll probably fix it later but in the meantime try changing the link like this.

http://www.asianfanfics.com/browse/tag_rated/sehun/L

this is the link to m rated fics for Sehun and that L at the end is for the latest stories. You can change that easily on the site. for going to the next pages just add /20. since there are 20 fics in one page the second page /20. the third page is /40 and the forth page is /60 and so on.
like this:

http://www.asianfanfics.com/browse/tag_rated/sehun/L/20
http://www.asianfanfics.com/browse/tag_rated/sehun/L/40
http://www.asianfanfics.com/browse/tag_rated/sehun/L/60

I don't know if you knew this or not but if you didn't then this is how you do it XD