There was much dispute about the book of Revelation in the early church. It was the last book of the Bible to be accepted as part of the Christian canon of Scripture. In the Eastern branch of the Church, distrust of Revelation persisted until the 15th century.
Early church tradition puts the time that the book was written as being at the end of Domitian’s reign. That would be A.D. 96. Though early church tradition also assigns the authorship to the apostle John, it is unlikely that John would have been still alive at that date.
Another factor to be noted, is that the author of Revelation states 4 times in the book that his name is “John.” Rev 1:1, 1:4, 1:9, and 22:8.
However, in the two books known to have been written by the apostle John, that is, the gospel of John and 1 John, John never mentions his name. And the author of 2 and 3 John refers to himself simply as “the elder.” The word “John” does not occur even once in 1, 2, or 3 John, and in its occurrence John’s gospel, it never refers to the author.