DMS Endpoint Connection Test Failed with Secret Manager

Test Endpoint failed: Application-Status: 1020912, Application-Message: Failed to retrieve secret. Unable to find Secrets Manager secret, Application-Detailed-Message: Unable to find AWS Secrets Manager secret Arn 'arn:aws:secretsmanager:<region>:<account>:secret:XXXXXXX' The secrets_manager get secret value failed: curlCode: 7, Couldn't connect to server Too many retries: curlCode: 7, Couldn't connect to server

Hi, I'm doing a DMS Endpoint connection test between Priavate VPCs. I'm fighting the above error.

I set it up as below.

• VPC1: Replication instance
• VPC2 : Mysql RDS (admin password with secret manager)
• The VPC is on the same account.

I also created a SecretManager VPC Endpoint on VPC1,

and the IAM Role connected to the DMS endpoint... This role has the following policy:

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": "secretsmanager:GetSecretValue",
            "Resource": [
                "arn:aws:secretsmanager:<region>:<account>:secret:XXXXXXX",
            ]
        },
        {
            "Effect": "Allow",
            "Action": [
                "kms:Decrypt",
                "kms:DescribeKey"
            ],
            "Resource": "arn:aws:kms:<region>:<account>:key/*"
        }
    ]
}

Here is the role trust policy:

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Principal": {
                "Service": [
                    "dms.amazonaws.com",
                    "dms.<region>.amazonaws.com"
                ]
            },
            "Action": "sts:AssumeRole"
        }
    ]
}

but the connection is not possible.

If I test the endpoint connection without using SecretManager with the same user password value, it will connect well. What's the problem? Please help me.