Whenever I try to evaluate code I get the following:

Evaluation of this xxxxxxx code-block (xxxxx) is disabled.

Sometime I evaluated these code-blocks, I don't know what has changed since the last time they worked.

I've tried with sh and ledger codes with the same results.

I've read the manual but I haven't found anything about it.

Org-mode version: 8.3.3

Emacs version: 24.5.1

;; Babel

(org-babel-do-load-languages
'org-babel-load-languages
'((R . t)
(emacs-lisp . t)
(gnuplot . t)
(calc . t)
(ditaa . t)
(latex . t)
(org . t)
(sqlite . t)
(sh . t)
(dot . t )
(sql . t)
(lisp . t)
(ledger . t)
))