Sorry but this looks a lot like OOTP but is there a way to set levels such as hard/average/easy?
When I try it, it always says "no offers"

I don't know what the reference to OOTP is in terms of but no there is not a "trade level" - because of the salary rules in regards to trading its not necessarily an issue of trading being hard its that possibly the player you are trying to trade is just very difficult to trade because of a contract or something like that. For example if you have a bad player on a multi year large contract no team is going to want him because they can't get rid of him and would just be saddled with him on their roster for the length of the contract.