Cloudwatch expressions not working


I’m trying to set up grafana for cloudwatch and I cannot seem to get the expressions to work despite having it set up almost identically to the example screenshot on the docs.

Here is my original metric (just random test data):

And when I try adding an expression I get this:

Note that this is nearly identical to the example given on the docs here:

This is a fresh install on debian using the latest debian image and grafana repository.
There are no messages in /var/log/grafana/grafana.log

looking at the query editor the response returns just an empty array.

Is there anything I’m missing or something perhaps set up incorrectly?

Kind regards,