Does it help to set s3-ext-signatureversion to 2 (instead of the default 4) in Advanced options?
Sometimes compatible storage is just mostly compatible. Version 2 worked around the issue below:
‘s3 compatible’ storage does not work with Signature version 4 #3970
and probably went into the writeup below, which might give some other ideas on working with yours:
Home > Third-Party Tools > Duplicati
I’m starting to wonder if it may be non-support for Signature Version 4 streaming.support doing this?
Have you asked your service provider? I’d hope they have an idea of what compatibility issues exist.
References:
Make S3 Signature v4 Streaming Optional #523
This causes compatibility issues with S3-compatible object storage services that support v4 sigs but not streaming; for example, minio and Oracle Cloud Infrastructure.
S3 compatible connection settings
enable_signature_v4_streaming Set to true to enable HTTP chunked transfers with AWS v4 signatures. Oracle Cloud S3 needs this to be false
OpenStack Object Storage (swift) – Support for Sigv4-streaming
Container for the parameters to the PutObject operation.
UseChunkEncoding If this value is set to true then a chunked encoding upload will be used for the request. Default: true.