Hello. The situation below has started to occurs in a only journal:
The journal had been working normally until this moment. What might be happening?
Hi,
well that looks… interesting. 
You have enabled “Google embedded viewer” (under “System Plugins” - “Generic Plugins”) for that journal. I am not familiar with this plugin but it looks like it is broken. The URL in the iframe that should show the PDF-file is
src="//docs.google.com/viewer?url=http%3A%2F%2Frevistas.unicentro.br%2Findex.php%2Fambiencia%2Farticle%2FviewFile%2F3561%2Fpdf&embedded=true"
which is wrong as the part pointing back to your journal (http://revistas.unicentro.br/index.php/ambiencia/article/viewFile/3561.pdf) is not working.
I am using the “PDF.JS PDF Viewer Plugin” (also in the “Generic” section) and it works quite well:
https://webapp.uibk.ac.at/ojs2/index.php/ciss/article/view/36/4
Greetings
Hermann
The Google view URL looks ok to me. That last escape of “%2Fpdf” expands to “/pdf”, so the correct URL is http://revistas.unicentro.br/index.php/ambiencia/article/viewFile/3561/pdf and that works.
Is it possible that something has change which is blocking Google’s access to your server?
Hermann thanks, it was this.
Ctgraham, the option was activated for mistake by the user.
[]´s
hello. do you know how to embed pdf like this using pdf viewer plugin?
hello. do you know how to embed a pdf? can u help me? =D