Unable to play multiplayer with version 1.17.0 or later

Since the 1.17.0 update, I'm having trouble connecting to multiplayer in a world I've created and hosted as a world.

 

In versions prior to 1.17.0, I was able to connect without problems, and I was always able to play multiplayer with 10 or more players, but after the update I can not connect to the world I set up. Even if you can connect, only one person can do it, and it continues to be impossible for a large number of people to participate.

Also, since I can join the world hosted by other people (platform is verified with both Switch and Win10) without any problem, I can not solve it no matter how much I investigate the cause. You may have a problem only for yourself, but if you want to solve it, you don't know how to solve it.

 

What I did as much as I could

・ Restart Minecraft

・ After deleting a friend, reapply and verify if you can connect

・ After backing up, uninstall Minecraft and then reinstall it.

・ Review settings such as firewall

 

I've tried all of these, but I haven't solved them at this point and I'm still unable to play multiplayer in the world I hosted.

 

I'm not very good at English, so I'm sorry if my explanation doesn't come across.