TransferUtility works on several PC's but not a new one.

I have the follow code snippet working successfully on at least 2 PC's (Windows 10, Visual Studio 2019)

gAWSAccessKey = "***************"
        gAWSSecretKey = "***********************"
        Dim gClient As New AmazonS3Client(gAWSAccessKey, gAWSSecretKey, gRegion)
        Dim fileTransferUtility = New TransferUtility(gClient)
        Try
            wPath = wArgs(0)
            wFile = wArgs(1)
            Console.WriteLine("Archiving " & wFile & " to Cloud ")
            'wPath = "C:\G-Apps\GABL\GABL-pictures\"
            fileTransferUtility.UploadAsync(wPath, gBucket, wFile).Wait()

I have just tried to copy this code to a new PC (Windows 11, Visual Studio 2019)

But when I execute the code I get :-The request signature we calculated does not match the signature you provided. Check your key and signing method. But the keys are working on my other pc's. How do I get new keys? And if I have new keys, will the existing pcs start to fail - can the system cope with different keys?

Thanks