second IAM account throwing RequestError when connecting to MTurk sandbox

Hello,

Given the situation where one IAM user is able to access the Amazon Mechanical Turk (MTurk) sandbox successfully while the other encounters an error, it suggests that the issue might not be with the AWS account linkage to MTurk itself (since one user is working fine) but possibly with the way permissions are set up or inherited for the second IAM user, or a peculiarity in the MTurk service's recognition of IAM user credentials.

• Firstly, I would recommend to verify that the second IAM user truly has the same permissions as the first. It's possible that a step might have been missed or a permission may not have been applied correctly.
• Secondly, you should ensure there are no policy statements that explicitly deny access to the MTurk operations for the second IAM user.
• Thirdly, If you accidentally use the wrong access key ID or secret access key, or if there was a mistake when configuring them in your application or development environment, your requests will not be authenticated correctly.
• Lastly, for your second account, it's recommended to delete the existing access key, generate a new one, and then configure this new key within your application or development environment.