I'm not familiar with that exact mod, so I have a few questions:

Is the smithy expecting Iron or Iron Ore?
Are your workers picking up Iron Ore or Iron when gathering the stuff on the ground?
Are you using that Nordic mod along with the Colonial Charter mod?

In The North you will collect Iron Ore from the surface of the map or from mines. You then must smelt this iron ore at the Bloomery along with Charcoal. This process will create Iron Bloom - it is flagged as Iron - but it must then be processed further at the Smith's workplace or the Blacksmith into Iron, also with the aid of Charcoal.
You can now use the Iron to make Tools.

Is this the process you are doing? or just the smelting into Iron Bloom? this would explain why the iron limit is being reached and you are thinking you have Iron.

I managed to get a hold of the person who created the mod and they told me that both Iron Bloom and Iron are categorized the same so I just had to increase the limit.

The problem was that I just didn't understand which product I had. My workers were doing their jobs and the mod was the only thing running.

Thank you both for assisting me!