Silencers not available due to missing resource

I am using a silenced tranq sniper rifle (because why would you not?) and of course, the silencer runs out after a time. So, I called a supply drop but was told that "some items are not available because of a lack of resources". I look at the iDroid and could not find anything low or just empty.
I looked at the official guide but could not find anything about that.
As a work around, I can switch the silencer from the machine gun. But I would like to know what I am missing so I can get some more of that.
Any one encountered this and can enlighten me?
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Where to find suppressors Days Gone?
You'll likely find a suppressor pretty early on in Days Gone. All the silencers in the game are improvised out of oil filters, so you'll want to be checking inside the hoods of cars when possible. Most of the time you'll find scrap under the hood, but sometimes you'll run across a suppressor.Do you have to wait everytime you buy a suppressor?
No, when you purchase your next suppressor you will still need to complete the ATF application process, pay the $200 tax stamp and wait for approval. Silencer Central keeps your fingerprints and passport-style photo on file in a secured location making your future purchases fast and simple.How do you get a suppressor specialist in MGSV?
You can use your silencer on any firearm that you own. You can also use your silencer on other calibers firearms that are different than your silencer. The listed caliber on your approved tax stamp is the largest caliber that you can use your silencer for. Smaller calibers that can accept the silencer can be used.How To Fix t6r.dll (Missing File) on Black Ops 2 Plutonium! (100% WORKS)
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