S3 throws 500 when trying to restore snapshot to AWS ES 6.2 [cross-region] - elasticsearch

Question

Trying to restore an v5.3 ES snapshot from S3 to ES 6.2. Snapshot bucket is in us-east-1 and i'm trying to restore it to a Amazon ES cluster in us-west-2. It's a cross-account, cross-region restore operation.
Registered snapshot repository in the us-west-2 ES cluster as below
{
"type": "s3",
"settings": {
"bucket": "valid-bucket-name",
"server_side_encryption": "true",
"endpoint": "s3.amazonaws.com",
"region" : "us-east-1",
"role_arn": "valid-role"
}
}
Got the response as
{
"acknowledged": true
}
But, then when i try to restore a specific snapshot, S3 throws 301
{
"error": {
"root_cause": [
{
"type": "amazon_s3_exception",
"reason": "amazon_s3_exception: The bucket is in this region: us-east-1. Please use this region to retry the request (Service: Amazon S3; Status Code: 301; Error Code: PermanentRedirect; Request ID: D72EFE8A89F76F57; S3 Extended Request ID: in03KW452re297MDp3GQQRFjJhMRXeP4md+FU99CHZ7D4TQKz8PBuSZKoO3+IFd+wAxNApztG5Y=)"
}
],
"type": "amazon_s3_exception",
"reason": "amazon_s3_exception: The bucket is in this region: us-east-1. Please use this region to retry the request (Service: Amazon S3; Status Code: 301; Error Code: PermanentRedirect; Request ID: D72EFE8A89F76F57; S3 Extended Request ID: in03KW452re297MDp3GQQRFjJhMRXeP4md+FU99CHZ7D4TQKz8PBuSZKoO3+IFd+wAxNApztG5Y=)"
},
"status": 500
}
Repository is already configured with region us-east-1. Error message is not useful.
If i just specify the endpoint as #Michael-sqlbot suggested, then it will throw the following error
{
"error": {
"root_cause": [
{
"type": "amazon_s3_exception",
"reason": "amazon_s3_exception: The bucket is in this region: us-east-1. Please use this region to retry the request (Service: Amazon S3; Status Code: 301; Error Code: 301 Moved Permanently; Request ID: CC1853D0EF68B5F7; S3 Extended Request ID: nrbWmI3OiPLdrMcRT6FiOHJineYv6clmSf+GcXtBBwKSzfIEV2gmMZjWEDtyCIRQUg+dM/Vmawg=)"
}
],
"type": "blob_store_exception",
"reason": "Failed to check if blob [master.dat-temp] exists",
"caused_by": {
"type": "amazon_s3_exception",
"reason": "amazon_s3_exception: The bucket is in this region: us-east-1. Please use this region to retry the request (Service: Amazon S3; Status Code: 301; Error Code: 301 Moved Permanently; Request ID: CC1853D0EF68B5F7; S3 Extended Request ID: nrbWmI3OiPLdrMcRT6FiOHJineYv6clmSf+GcXtBBwKSzfIEV2gmMZjWEDtyCIRQUg+dM/Vmawg=)"
}
},
"status": 500
}
Update: I can confirm that it's a region/endpoint related issue with s3-snapshot-plugin. Created another cluster in us-east-1 (same region as that of bucket) and it worked with out any issue.

Answer 1

This seems potentially relevant:
Important
If the S3 bucket is in the us-east-1 region, you need to use "endpoint": "s3.amazonaws.com" instead of "region": "us-east-1". (emphasis added)
https://docs.aws.amazon.com/elasticsearch-service/latest/developerguide/es-managedomains-snapshots.html

Answer 2

Cannot comment on Michael's answer due to lack of reputation :-)
I tried their suggested workaround to set up a snapshot repo on a new 7.9 cluster in us-west-2 with a bucket located in eu-west-2 and it worked! Doesn't seem to be documented anymore though on Amazon's developer guide. I'll submit feedback to them.
BTW, if you're trying to migrate data from another cluster, don't forget to add "readonly": true to the settings object. This is just to prevent accidentally writing to that repo.