Test Ups Shipping "package Must Weigh More Than Zero Pounds"?

I have been through all the forums and cannot find an answer to this seemingly simple problem - maybe someone out there can help?

I am trying to set up real-time shipping with UPS but when I run a test, it says “package must weigh more than zero pounds” even though I enter weight in the test box. I have tried many variations of weight parameters in the configuration and it doesn’t seem to change anything.

Anyone have a solution? Thanks in advance!