The GfyCat folks stopped supporting an old version of their embed code, breaking lots of embedded animated gifs and videos all over the interwebs. This forum and many others rely on s9e's textformatter library to embed content like GfyCat videos. The library has been updated, but this forum's software will probably use the old library for a long time. I suggest manually updating the files in the library consistent with these changes: MediaEmbed: updated Gfycat · s9e/TextFormatter@7651e0c It worked for me on phpBB. Hope this helps.