I have an old WordPress blog that I have not used for the past two years. Now I want to use it again. I found myself unable to make any action from the back-end! I can not do any new operation, such as:(Make new page, new post, deactivate plugin, change theme,..etc).
In the hosting, I can upload files and they show up in the back-end (I uploaded new theme).
I have no idea why is that happening. I searched the net but nothing useful.