Daniel Alves the most buggy player in Beta.

There's a warning when you sign Alves that he won't be available until January, I'm afraid you must've missed it! 

Same thing happened to me. When you are asked to confirm, everything appears to be fine (no warnings or restrictions), but once you confirm and try to register him, he is unavailable. 

However, maybe you didn't notice it, when you first offer a contract to him, at the bottom of the page, it says that he won't be available until Dec 31...

I agree it's a total bummer...

11 hours ago, phd_angel said:

However, maybe you didn't notice it, when you first offer a contract to him, at the bottom of the page, it says that he won't be available until Dec 31...

 

That's the warning I was referring to I'm afraid - apologies you've missed it!

This was resolved as part of the 22.2 update, thank you for your patience. 
Please let us know if it appears again.