Sounds like you doing it right. Sometime decoys don't have a noticeable effect on the success rate. The size of the town you are spying on, if the player is active or inactive, and if they have spies in defense or even have a spyhut at all and the type of mission you are doing. These can all make decoys more or less effective. But you should see some change some of the time! Have you tried spying on different towns and different players?
For me, I've noticed that when the form of government increases spy defenses.
Also, the page may not have fully loaded.
Try a few other players.
Starman
I tried it on player who was active. When i put 5-6 spies it is at max chance of success around 71-73%. Before when i put 3-5 decoys with them my chance go up to 88-90% wich was good. Now it dont move even with 1% for the same amount of decoys. And it is from at least last two paches(maybe more i wasnt very active before). Chance to reveil my spies dont move too. And i am talking about missions in the city to spy warehouses or army.
I dont know how to change my quote so i want to add. For inactive players its the same (even if there is more easy) but i dont move even with 1% no matter how much decoys i put with my spies.
Sorry I can't help.
Some screenshots make it easier to understand the problem.
Starman
I have checked the topic and I can say decoys are working in generell.
There might be some specific issue, therfore we request some more information Romche
You can send us this information here or via support system if you doesn't like to tell such information public.
Since last update everything is working for now and i dont see the problem anymore.
