I decided to withdraw all my items into my backpack.
So the bot sent me a steam trade offer.
I checked "Confirm Trade Contents" and clicked accept trade.

Then it said :
There was an error accepting this trade offer. Please try again later.

You cannot trade with Dispenser 01 (Lv.1).

I tried doing this for 2 days now, and still cant get back my items. Please Help.
Thanks!

"You cannot trade with XXX" usually means the Steam Community session of your browser is partially expired. Try logout Steam Community and login again and see if you can accept it.