Kind of, but they can't do any business with a US based company. Many specialized products are only produced by a small handful of companies, and if all (or most) of those are US based, Cuba's SOL. They've also had problems where a supplier was bought out by a US based company, so now they can't buy that product anymore.

There's also the fact that it's far cheaper to ship goods to Cuba from the US then it is to ship goods from Europe or China. This means that even if they can buy some goods, they're often much more expensive then it needs to be.

The cost of shipping is more than made up for in the cost of labor and capital that goes into the products. Which is why most other countries use China as their number 1 trading partner. There is also nothing critical manufacured by the U.S. for Cuban agriculture that is not available elsewhere. They are a tropical island with one of the most ideal climates on planet Earth, food grows virtually all year there, nevermind the abundance in the ocean itself.

You should look into what US sanctions actually do. they effectively lock the country/people out of the international finance system

No, because they are under heavy sanctions that threaten any country that dares trade with them.

The origin of the sanctions goes back decades, to Cuba's land reform, where the government took back land from private corporations, such as United Fruit Company, who then lobbied the US to go after Cuba on their behalf.

Kinda.

  The United States has threatened to stop financial aid to other countries if they trade non-food items with Cuba… Despite the existence of the embargo, Cuba can, and does, conduct international trade with many countries, including many U.S. allies; however, U.S.-based companies, and companies that do business with the U.S., which trade in Cuba do so at the risk of U.S. sanctions.

- wikipedia

This article is about bread. Bread, perhaps the most simple, easily manufactured food on the planet. It doesn't even take fancy modern equipment to make - people have been making bread for thousands of years all across the world.

Cuba was settled 6,000 years ago according to Wikipedia - long before importing goods was even a concept. They did not, and still should not need to import anything to feed their population. The resources are misappropriated by their government - it's that simple.

Cuban's rely on the government to ration/provide ingredients to make bread. And just like the USSR, the government eventually fails to provide and the population - who became entirely dependent on the government - are left with no alternative means to support themselves. It's a tragedy that has bestowed damn near every single communist nation that has ever existed.

There is no valid excuse for not being able to make enough bread.

You need wheat to make bread. You can't grow wheat in the tropics. That puts embargoed countries like Cuba in a precarious spot.

Cuba can trade with most of the world...

Well. Kinda!

I'm going to go out on a limb and suggest that the population 6000 years ago was a some orders of magnitude lower than it is now.

and for most of its history didn't eat wheat