Add field, error sending the requests

Fri, 29 Jan 2016 03:33:40 -0800

In Section Editors, Modifying a Table, I click on the "Add Field" button, fill simple information, when I click on "Save" button, nothing happens, so I click in "Cancel" button or any other link in the page, then I got a message: There was an error sending the requests! (0 error), please see attached image, and the field is not added.

This error happens with any device using my internet connection using my WIFI or my broadband by cable, I have BT Infinity. When I use my mobile and 4G the error does not appear, so there must be something in my connection, I have reset the router and deactivate firewall but the error is still there.

I use Windows 7 and Chrome.

Can somebody help me?

Thank you very much in advance.

Daniel.