Failed to verify username error

So a few things.

Soo i was having this problem where minecraft was giving people who werent on my local network an error that they were logging in with an error that read “failed to verify username”. I am making this post today to try to help others who may have had a similar problem and whos problem was not fixed by the help of countless articles which say more or less the same thing. They say sign out of the launcher and sign back in, mess with the firewall, etc. After hours of digging around and looking at forums, articles, and whatnot and coming up with nothing. Not a single article with like 10 different things to do helped. I eventually turned to my and found a setting, “prevent-proxy-connections”. In amp its like disallow proxy connections. This solved it. I flipped the switch (turned true to false) and there we go, all fixed. Maybe someone can correct me but i think the reason this happens is because minecraft identifies playit as a proxy, or maybe the fact that i think online minecraft servers require u to authenticate ur instance of minecraft with their username servers cause this setting to activate when turned to true.

Regardless hope this can help some people.

Might be on the client’s side because for some reason if the hosts pc is running on ip4 minecraft throws a hissy fit if the games internet is ip6 but there are situations to get around that

Idk if this disproves what ur saying but im pretty sure if ur network is ip6 capable, playit will default to that, and since my network is ip6 capable, i think my server computer should be using ip6. I think u might be talking about something different tho. Do u think the people joining my server are on ip6, which is causing the disallow proxy connections being true to be triggered?

I am using AMP by Cubecoders.
I figured out what was causing this issue. I know this issue is old but its still valid.
I too had the same circumstances as you. But if I hosted a server using a java command instead of AMP, it worked! I guess AMP would prefer the server to be port forwarded it rather than tunneled. I’m not sure why, I just know this because it only happened to people using the playit ip but me connecting using the local IP worked fine.
Hope this helps 2 months later.