Greyed out spy options

[kkapalk]

Hi, could anyone tell me why my spy's option to steal plans from my opppnents is suddenly greyed out and I cannot use that option. Nothing has changed regarding trade and such like, just the greying out of that particular option. I have two spies, in different opponents' lands and neither can perform the action. They both could do this previously.
Thanks,
Kev.

 

[Howitzah]

Do you have enough money?

 

[kkapalk]

That's it, do I feel a fool. I didn't check the money situation. Thankyou.