Thread:Project:Support desk/Widget:Google Spreadsheet refused

All the sudden my Widget:Google Spreadsheet (e.g. http://drebbel.net/wiki/Biographies) started to fail with a Refused to display 'https://spreadsheets.google.com/...' in a frame because it set 'X-Frame-Options' to 'SAMEORIGIN'. message. This is the sheet. (published and shared anyone with the link) Widget:Google Document however works fine ... Published everything the same way.

don't change anything.
 * Manual:$wgBreakFrames
 * Manual:$wgApiFrameOptions and similar

My site is drebbel.net/wiki

Any idea?

Thanks in advance.