The VSA proxies require connectivity to the following regional and global endpoints to support backup and restore operations:
Regional Endpoints
ebs.<region_code>.amazonaws.com
ec2.<region_code>.amazonaws.com
ssm.<region_code>.amazonaws.com
sts.<region_code>.amazonaws.com
kms.<region_code>.amazonaws.com
Global Endpoints
s3.amazonaws.com
iam.amazonaws.com
sts.amazonaws.com