Can't Research (HOTU Version)

[6750aea75e5e6RedSwirl]

I'm on deck 3 where I have to research some stuff, but for some reason when I start researching on somethings, it'll stop at around 5% and no matter what I do I can't resume the researching.

Could this be a glitch or am I just not doing it right?

[6750aea75e88fKolya]

You may simply be missing a chemical element. You should get a message about it when research stops. Check your message log if you missed it. Default key is L.