Description is internally inconsistent.

.. which accepts an array of integers ..

however

If the sum cannot be calculated, 0 should be returned.

Also, this is implemented completely arbitrarily.

In Haskell, the sum can always be calculated. In JavaScript, there are tests with all sorts of weird unspecified Non-Arrays, but if the input is an Array, it's always an Array of Numbers.

There is generally no good reason to pollute kata with input validation; if anyway, the description should just state plainly input validation is to be performed instead of hinting that the sum might be impossible to calculate, and it should be tested better ( more consistently across languages is, unfortunately, just plain impossible. the Haskell description might be adjusted for that ).

It's... A corner case. Means you should print the input to see what's your function is fed with and so you'll be able to understand why it fails.

Help us help you. Tell us which language you're having this problem with, and markup your code as code ( with correct indentation! ).

It looks like JavaScript though, in which case: console.log is your friend. Look at the inputs.