Installing cargo lambda via scoop commands and aws cli via the installer. For the env this is a windows machine with nothing special.

I found this old reference to a similar issue, but I don't know why your system can be affected by it: awslabs/aws-sdk-rust#468 (comment)

I'll make an issue / discussion on aws-sdk and see. Very very odd that this is happening across multiple machines.

I have found the solution to this.

For whatever reason in this case, if the AWS CLI command is used the certificate will validate. When using the Cargo Lambda commands, the certificate used would not validate and return the error.

Downloading any of the Amazon CA certs from - https://www.amazontrust.com/repository/ and importing this via the Windows wizard into the Trusted Root CA then generates the CA twice - its like it unhides / marks as trusted the original CA that existed. This solves the issue and allows the Lambda console to approve the request.

While this solves the problem it doesn't 'explain' how / why the Cargo Lambda commands are not validating the existing certificate like the AWS CLI commands are.

This may also be unrelated to Cargo Lambda and could be some magic that Windows did with an update which either untrusted an Amazon CA or something but there 'aren't' any other issues / discussions seen in these channels so far (which makes this potentially unlikely) and debugging further here is way above my skill set.

Really appreciate the help and your time!

Thanks

I'm glad you were able to figure it out!