Can't change players number to 128 after upgrading my account

Hello, I updated from 64 to 128 but still the server reading only 64 players and get message
Using 128 slots with ‘Element club Aurum’ requires you to enable OneSync ‘on’ ( formerly named ‘Infinity’)

Anyone can help me please to solve it?

My plan is: Element Club Aurum 25/Month

You need to enable that mode.

Thanks for your reply, can you tell me how to enable it please

Go into your txAdmin - Settings - FXServer and turn it on. Remember to restart your server after making this change.