Issue in endpoint region, it is not using the region configured

Note: I am assuming you are not using a custom host, if so that should be removed first.

the region is blocked and it is showing eu-south-2 after saving the configuration.

We obtain this from AWS. AWS believes the bucket is in eu-south-2, if this is incorrect than AWS internally is going to have a significant problem.

teacher.-bucket
Is this the actual bucket name? IIRC a hyphen is not permitted at the start of a hostname portion, was this suppose to be teacher-bucket or is this an older path based only bucket?

I don't know why the enpodint is pointing to eu-south-2

I've seen AWS redirect across regions. I suspect we are connecting to us-east-2 and AWS is redirecting us to eu-south-2 (as that is where they believe the bucket is located) where the region field (set in the API locally) now indicates a mismatch and AWS rejects the request.

Other possible thoughts: is this a multi-region access point or an accelerated access point?

The bucket was created in us-east-2 region, however, for any reason, the region saved in the sf3fs config form is eu-south-2.

for any reason, the region saved in the sf3fs config form is eu-south-2.

https://docs.aws.amazon.com/AmazonS3/latest/API/API_GetBucketLocation.html
As noted in #2 We use the AWS API to obtain the location. That value comes directly from Amazon Web Services.

Still awaiting answer to the other questions from #2 to attempt to move this forward.

Other possible thoughts: is this a multi-region access point or an accelerated access point?
I ran the command
aws s3control list-multi-region-access-points --account-id XXXXXXX

And it shows:
An error occurred (PermanentRedirect) when calling the ListMultiRegionAccessPoints operation: This API operation is only available in the following Regions: us-west-2. Make sure to send all future requests to a supported Region.

I am unclear on what you are trying to say in #5. All that was posted was an error message indicating an AWS Client configuration error.

teacher.-bucket</bucket> I've checked with AWS and they confirm <code>Bucket name must not contain dash next to period. This appears to be the first error based on the details provided.