Weird multimedia library error!!! Pls help

I have this unsual behavior on my site. When i manage content through the library i have no problem.

But when i want to insert a media content on a post, the library window can’t show me any content. It stays loading to eternity….

I’ve manage to get around it, inserting content through html… but now i need to solve this since i can’t insert a feature image to the post.

PS: Once on a post, if i “Add multimedia” and decide to upload an image, i get a “error, come back later”, but if i do this directly through the library on the backoffice, all goes fine.

Please help, and pardon my englis.