I have modify the "backpack.server.toml" at both side,like this image,just add some items to blacklist.

When I'm in server environment,my config doesn't work,I'm not using third-party's server,Only forge original server.

But when I back to my singleplayer world,my configuration is in effect, and the items I added to the blacklist will not be placed normally.

Forge version: 47.3.22 ; My mods: backpacked-forge-1.20.1-3.0.0-beta.9 , curios-forge-5.11.1+1.20.1 , framework-forge-1.20.1-0.7.12

You're editing your local config, not the config on the server. You need to edit the config stored on the server.

You're editing your local config, not the config on the server. You need to edit the config stored on the server.

Yes, I'm doing that
The configuration file on the server side is exactly the same as the configuration file on my local client,However, blacklisted items cannot take effect on the server, even if the configurations of the two sides are synchronized.

That config in particular is synced to the client when you join the server. The client version does not override the server version. My guess is that you are not receiving the data. Is there anything special about your server setup, e.g. software, proxies, certain host?

That config in particular is synced to the client when you join the server. The client version does not override the server version. My guess is that you are not receiving the data. Is there anything special about your server setup, e.g. software, proxies, certain host?

My server program run at my PC,Because I haven't public IP,I'm using Virtual LAN software to play with friends.
However,because server program at my PC,so I can connect by 127.0.0.1,It's still have this issue.
And when I'm testing for this issue,I haven't another mods just this mod.