Some cracked users can't join my 1.17.1 server with 1.17.1

I made an aternos server with 1.17.1 spigot. But there's this weird problem that some friends of mine who are using cracked clients can't join the server with 1.17.1. They need to join with 1.16.5 (the server has viabackwards) but they are missing out on a lot of 1.17.1 features and this ruins the main reason for making a 1.17.1 server. They have also noticed that they can't also join other ATERNOS servers with 1.17.1 but it works with other non-aternos 1.17.1 servers. Why aternos please look into this problem and fix it as soon as possible.

THANK YOU.

The screenshot below should explain it. It simply says connection lost and you were trying to connect to aternos. Also as i said it doesnt occur to every person. Many other cracked friends of mine can join but also many cant.

And they have tried every way but it is not getting solved.

Quote from Roman

You're probably hitting a TLauncher bug.

Use the address that is displayed in the screenshot.

Ok. Thank You So Much. It is alright now. They are able to join.