Problem with Trade and sell game

[Σ>―NOKIA(33°ω°10)♡→✅]

Hi, When i try sell game it's show's me like 
Troubleshooting:

• Make sure that your privacy settings are set to public¹.
• If you are a F2P user, check your Steam inventory to make sure that you own any tradeable² items that we accept.
• Sometimes we cannot load backpacks from Steam. Please try again or wait until Steam is working again.

¹ private, friends only, logged in users only will not allow us to retrieve your backpack data
² tradeable items do not have (not tradeable) in their item description, as F2P you can only trade items you received from other players

And with Trade when i press accept its show's this message 

ACCEPT TRADE

There was an error accepting this trade offer. Please try again later. (25)

[Gaia's Minion]

2 hours ago, Σ>―NOKIA(33°ω°10)♡→✅ said:

1. You seem to have your inventory as Private so that means no one can send you trade offers.

2. Error 25 is "Limit Exceeded" which means one of the two users involved doesn't have enough Empty Slots to accept all the items in the trade.