Getting AuthFailure with AWS Authorization

Please search for related topics, and then read through the guidelines before creating a new issue.

Describe the bug
Setup a GET to https://ec2.amazonaws.com/?Action=DescribeInstances.
Selected AWS Authorization.
Added AccessKey and SecretAccessKey
Set Region to us-east-1
Set ServiceName to execute-api
Clicked UpdateRequest
Clicked Send

Getting back Status 401 with

<?xml version="1.0" encoding="UTF-8"?>

AuthFailureAWS was not able to validate the provided access credentialse6ffc9b3-e599-4010-b86e-59e426e732d8

Having issue with chrome client as well as native Postman 7.6.0 on Mac Mojave.

Verified that AK/SAK works as expected using AWS CLI

To Reproduce
Steps to reproduce the behavior:

  1. Go to ‘…’
  2. Click on ‘…’
  3. Scroll down to ‘…’
  4. See error

Expected behavior
A clear and concise description of what you expected to happen.

Screenshots
If applicable, add screenshots to help explain your problem. Please make sure images or code samples don’t contain authentication tokens or credentials.

App information (please complete the following information):

  • App Type [e.g. Chrome App, Native App]
  • Postman Version [e.g. 6.0.1]
  • OS: [e.g. macOS High Sierra 10.13.2]

Additional context
Add any other context about the problem here.