I have a strange issue. When every one use trade post it work perfectly, but when i want to add items on admin then i cant.

what's the server ID ?

server ID is 4662

I can't reproduce the issue here.
Opening the trading UI windows in GM mode on this server works fine in every trading post.
what do you do to receive this error?

I open server trade post on gm mode. only this one. trade posts without this option work normal. on gm mode to. but this one work ok without GM mode.
Player trade post on GM same trade post Without Gm Server trade post on GM And same trade post without Gm mode

I found solution. I deleted old trade post and make new. now it works.