Issue offering contracts to unattached players

I wondered if anyone could explain this to me. I offered an unattached player a contract. He chose someone else, but the deal fell through. I now want to offer him a contract again, but the game won't let me. All I get when I click "Approach to Sign" is the below:

Is this something to do with a real-life rule?

I think this might be a small bug with the game. I'm sure I've had the same issue once or twice. After a couple of weeks, if he's still unattached, try offering again. Iirc, it was a matter of waiting 2-3 weeks before I could offer the contract again.

In the end, it turned out that once he'd started negotiations with someone else, I could offer one. A bit odd.

Didn't matter in the end. Couldn't get a work permit for him.

Another issues raised by this player is that A-League sides keep agreeing contracts with him and then it falls through because they already have a Marquee player. You'd think the AI would already know that.