Thanks for replying.
Yes, whenever I run yarn start-with-mock-data everything works.
Indeed I altered the variables in the packages/api/.env file and ran yarn start afterward.
The browser I use is Firefox but I do not think that is the issue as the mocked data works in Firefox.
Moreover, CCF links correctly to Athena as I received an error message earlier that the column product_vcpu was not present in my database.
After I added this column manually in Athena this error went away and I received the error that I forwarded in my question.
So I do think my billing/usage data is in the wrong format somehow but unsure how I can solve this.
In my AWS account, I only have S3 instances and no compute instances so maybe that could cause a problem?
And I have quite some empty columns in the billing table.
Thanks a lot.