Not Recognizing Apostolic Authority

3 John 1:9-10 (ESV)
I have written something to the church, but Diotrephes, who likes to put himself first, does not acknowledge our authority. [10] So if I come, I will bring up what he is doing, talking wicked nonsense against us. And not content with that, he refuses to welcome the brothers, and also stops those who want to and puts them out of the church.
“Does not acknowledge our authority.” I try to wrap my head around this phrase. Of course, this letter falls within the antilegomena. So there were many in the early church that didn’t recognize the authority of this letter, because they were not sure John, the disciple wrote it. To this day we still aren’t. All authority rests on this. Did the author have apostolic authority to write. Yet the letter has been retained, and included in many Bibles with at least a probability that it was actually John who wrote it, and not some other John Doe. It seems hard for me to think that John’s authority would be challenged by anyone in the church. How would you contest that?
Of course, we know that by the end of John’s life many Gnostic sects grabbed hold of the Story of Jesus, and twisted it into their own warped theologies. John it is said left a Bath naked once because one of these men had entered and he didn’t want to be in the same building, lest it should cave in. So it is perhaps very likely that even someone who had become a pastor had turned to itch his ears with the Gnostic deceit, and with that ignored John and his authority.
This happens even today. Pastors leave faithful doctrine, begin to preach against God’s law, and rather than forgiving sin, they excuse it, all the while all but ignoring the death and resurrection of Christ. It is incumbent on the congregation to hear what their pastor is saying, understand it, and challenge it if it is wrong. I say that, but do it in a tactful manner if you think it needs to be done. Sometimes people get upset over what they think they heard, or are just confused. This is a time to ask questions with charity. If after first asking in charity, you still find that the pastor is teaching falsely, you have a duty to go elsewhere, or work to see the pastor repent, or get rid of him and call someone new to teach God’s word faithfully. But be careful that you are not the one that is wrong.