Found what might be an issue, go to your configs folder, go into gregtech, open up recipes. There are 2 sections for storage blocks:
storageblockcompression { ... }
and
storageblockcrafting { ... }
By default all of the ones in storageblockcompression should be set to true{except copper} while the others should all be false(except for copper since you use the compressor to make dense copper plates). Make sure it's set to true for iron in at least one of the two locations.