Getting AWS Production parameters from parameters store vs QA

In AWS QA env I am able to get AWS parameters from parameter store.

My username in QA AWS cloud is abc.xyz (firstName=abc, lastName=xyz) I do the following and I am able to get the parameters from AWS parameter store no problem using :     RoleArn-QA = "arn:aws:iam::12345:role/mySecrets"    stsClient = boto3.client('sts')    assumedRoleObject = stsClient.assume_role(RoleArn=RoleArn-QA, RoleSessionName=RoleSessionName, ExternalId = ExternalId)    session = Session(aws_access_key_id=assumedRoleObject['Credentials']['AccessKeyId'],                      aws_secret_access_key=assumedRoleObject['Credentials']['SecretAccessKey'])    client = session.client('sts')    accessKey = str(assumedRoleObject['Credentials']['AccessKeyId'])    secretKey = str(assumedRoleObject['Credentials']['SecretAccessKey'])    SessionToken = str(assumedRoleObject['Credentials']['SessionToken'])    store = EC2ParameterStore(        aws_access_key_id=accessKey,        aws_secret_access_key=secretKey,        aws_session_token=SessionToken,        region_name=awsRegion)

However in prod given my username in prod is: axyz this user is a trusted user for role ARN mySecrets or (arn:aws:iam::6789:role/mySecrets)

    RoleArn-Prod = "arn:aws:iam::6789:role/mySecrets"

When I run similar code for Prod given new RoleArn-Prod

       stsClient = boto3.client('sts')    assumedRoleObject = stsClient.assume_role(RoleArn=RoleArn-Prod, RoleSessionName=RoleSessionName, ExternalId = ExternalId)    session = Session(aws_access_key_id=assumedRoleObject['Credentials']['AccessKeyId'],                      aws_secret_access_key=assumedRoleObject['Credentials']['SecretAccessKey'])    client = session.client('sts')    accessKey = str(assumedRoleObject['Credentials']['AccessKeyId'])    secretKey = str(assumedRoleObject['Credentials']['SecretAccessKey'])    SessionToken = str(assumedRoleObject['Credentials']['SessionToken'])    store = EC2ParameterStore(        aws_access_key_id=accessKey,        aws_secret_access_key=secretKey,        aws_session_token=SessionToken,        region_name=awsRegion)

I get this error

botocore.exceptions.ClientError: An error occurred (AccessDenied) when calling the AssumeRole operation: User: arn:aws:iam::12345:user/abc.xyz is not authorized to perform: sts:AssumeRole on resource: arn:aws:iam::6789:role/mySecrets