After all of this headache, I went back to 2.7.1, but I had to rebuild all the blog, get the plugins, themes and import all the post from the previous one. It took me like 2-3 hours, but it worked and now seems to work well without problems. I even had to do a new sub domain so I can make everything work right.

Anyway, I came to the conclusion that moving to 2.8, just like that may cause a lot of issue, so at the moment I’ll stick to something older, but more stable. I can’t say that it’s a bad idea to upgrade to 2.8, but from my small experience, it can be hell.

Good luck!