Without a screenshot of your tech tree it's impossible to say. Did you pay the Forge Points and then click on the "Unlock Now" button? You have to click the button or the tech does not count as researched. If you did click on that button and it's truly researched, then you should contact in-game support to look into it.After researching economics and checking the gold box, I am not able to use.
playing on windows 10 PC with Firefox browser. Thank you for any help
you should contact in-game support to look into it.
@Mighty Mongoose, I just looked at your guild. They say in their description that they are no pressure, but they are also apparently no help. You should have been able to ask the guild leaders about this and gotten the answers you got here.
You should definitely contact support in-game and open a ticket on it. Either use the settings button or just right-click anywhere on your city screen (PC).