Issue connecting from Redash to DynamoDB - Unknown Error occurred

Hello Redash Community,
Just signed up for a free 30 day trial. Tried to create a data source to DynamoDB. Already gave access to the IP address 52.71.84.157 (for ALL Traffic) on my default security group.

Provided the correct Access Key and Secret key. When testing, get the following error.
Connection Test Failed:
Unknown error occurred while performing connection test. Please try again later.

Any help or suggestion is much appreciated!

Thanks,
Ramesh

Thanks to Jesse from Re:Dash for working with me on this - looking at the logs etc.

Finally it worked! I had to create a brand new IAM user in my AWS account and gave that user read only permission to my tables in DynamoDB via a policy. Then gathered the access and secret key for that user and provided it in the data sources connection dialog. The test connection was successful.

There is no need to add any IP address on the AWS side because DynamoDB works based on public DNS and outside of a VPC.

Thanks,
Ramesh