Though it was referenced by Clement, likely used by the author of the Apocalypse of Paul, and was included in the Muratorian Canon (c.200 C.E.) as well as the Codex Claramontanus, it was omitted from other canon lists. It is difficult to speculate why it fell out of favor in the orthodox church. It probably included several contributing factors: 1) the church was very leery (and increasingly embarrassed) by apocalypses in general. Even John's was constantly argued about, and notably absent from several of the early canon lists. 2) the Apcalypse of Peter was often associated with the heretical Gospel of Peter in the minds of many, especially heretics, even though the works have no notable similarity to eachother, and the wording and styles are very different and evidently the work of two very different authors. 3) "It was not recieved", meaning outside of Italy, it was essentially unknown in most of the other apostolic churches (that is the ones founded by the actual apostles) - most importantly, it wasn't in their collections. 4) "It was judged not to be Apostolic", meaning it lacked an adequate reputation among the apostolic churches for being authored by one of the Apostles or one of their immediate associates/disciples. 5) it was non-liturgical - it did not form a part of the common worshipping life of the churches - nor had it ever. Hope that helps.

2-18-2017 Isaiah 55:11 "so is my word that goes out from my mouth: It will not return to me empty, but will accomplish what I desire and achieve the purpose for which I sent it." God Himself maintains the integrity of His word. If God wants this or that book to be in the bible, it will be so. He allows just enough human error to let us demonstrate that we are not capable of maintaining it.