More Information Link – Some Showing Page Not Found Others Not

I am having the same problem that someone else that posted here was having, but there was no answer on it.

Some of my products link to more information: https://www.midamericatruck.com/product/791-2003-ihc-8600/

Others don’t link to more information but show a Page Not Found: https://www.midamericatruck.com/product/556-1984-amgen-4-x-4/

Both of them link from the main page here: https://www.midamericatruck.com/trucks/

Can you help?

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