Setting up a new US account, but it says my zip code is invalid. Why?

[pastorpaul]

I am in Montana, and have a Montana business.  I am attempting to create a business account and when I go to enter my basic information and get to my zip code, it says it is invalid and will not let me go any further.  The zip code I am entering is not invalid.  What is going on and what can I do to correct it?

[sharpiemarker]

@pastorpaul 

Do a zip code look up in the USPS database to double check:

https://tools.usps.com/go/ZipLookupAction!input.action

And if you’re using the full 9 digit, try using just the 5 digit.

[pastorpaul01]

Thank you.  I have tried both of those approaches and neither work.