friend cannot join my server

[g00se__]

So my friend is trying to connect to our server and it won't work. At first, it was because I needed to add Via Version so she could join from 1.17, but now it's just giving her an error message without the outdated client part. The dashboard says the server is online, so it's probably not that too many servers are online. I have tried looking it up but most things are more specific or different. What are the reasons that she may not be able to connect and how can we fix it? Sorry if this isn't enough information and thanks for any help

[_Tarna_]

What is the error your friend is getting when they try to join? Are you able to join fine? Just try telling them to use 1.16.5 cause the servers are still on 1.16.5 anyways.