Thank you. I already did that but it didn’t work. The fact is that the mail notification is sent in the language in which the admin is using wordpress. In my case my site has two admins, one that uses wordpress in Italian and another that uses wordpress in Catalan. The solution is that entries at guestbook written in Catalan have to be approved by the admin that has wordpress in Catalan, and viceversa.
Thanks again.
You saw that because I tried to change it from recipe-category to category, but it didn’t work before either. I don’t think it’s a permalink issue…
