Error authorising ServiceM8 to execute lambda function

As per https://github.com/servicem8/addon-sdk-samples/tree/master/hello-world-addon-python , I have set up an AWS account and created an index.py :
https://us-east-2.console.aws.amazon.com/lambda/home?region=us-east-2#/functions/servicem8-addon-sdk-hello-world-function

I then ran:
aws lambda add-permission --region us-west-1 --function-name servicem8-addon-sdk-hello-world-function --statement-id 123 --principal 576043501240 --action lambda:InvokeFunction

But I got the following error:
Unable to locate credentials. You can configure credentials by running "aws configure".

I tried changing the region to us-east-2 to match where my function seems to be but I got the same error. This is my first time developing in AWS so hopefully, it's something simple.