Cannot backup to SeaweedFS objectstore

When creating ObjectStore CR that points to SeaweedFS s3 objectstore it starts uploading the wal archives, makes a .upload directory, but then I got the error:
`
{"level":"error","ts":"2025-12-16T10:46:23.075022375Z","msg":"Error while handling GRPC request","logging_pod":"postgresql-1","info":{"Server":{"Client":{"Client":{}},"InstanceName":"postgresql-1","SpoolDirectory":"/controller/wal-restore-spool","PGDataPath":"/var/lib/postgresql/data/pgdata","PGWALPath":"/var/lib/postgresql/data/pgdata/pg_wal"},"FullMethod":"/cnpgi.wal.v1.WAL/Archive"},"error":"unexpected failure invoking barman-cloud-wal-archive: exit status 4","stacktrace":"github.com/cloudnative-pg/machinery/pkg/log.(*logger).Error\n\t/go/pkg/mod/github.com/cloudnative-pg/machinery@v0.3.1/pkg/log/log.go:125\ngithub.com/cloudnative-pg/cnpg-i-machinery/pkg/pluginhelper/http.(*Server).Start.logFailedRequestsUnaryServerInterceptor.func2\n\t/go/pkg/mod/github.com/cloudnative-pg/cnpg-i-machinery@v0.4.1/pkg/pluginhelper/http/grpc.go:53\ngoogle.golang.org/grpc.NewServer.chainUnaryServerInterceptors.chainUnaryInterceptors.func1\n\t/go/pkg/mod/google.golang.org/grpc@v1.76.0/server.go:1234\ngithub.com/cloudnative-pg/cnpg-i/pkg/wal._WAL_Archive_Handler\n\t/go/pkg/mod/github.com/cloudnative-pg/cnpg-i@v0.3.0/pkg/wal/wal_grpc.pb.go:196\ngoogle.golang.org/grpc.(*Server).processUnaryRPC\n\t/go/pkg/mod/google.golang.org/grpc@v1.76.0/server.go:1431\ngoogle.golang.org/grpc.(*Server).handleStream\n\t/go/pkg/mod/google.golang.org/grpc@v1.76.0/server.go:1842\ngoogle.golang.org/grpc.(*Server).serveStreams.func2.1\n\t/go/pkg/mod/google.golang.org/grpc@v1.76.0/server.go:1061"}
`

However, with awscli I can reach the bucket and can upload objects

Objectstore definition
`
apiVersion: barmancloud.cnpg.io/v1
kind: ObjectStore
metadata:
name: azure-backup-store
namespace: postgres
spec:
# Base configuration for Barman Cloud to connect to Azure
configuration:
destinationPath: "s3://backups"
endpointURL: "http://seaweedfs-s3.seaweedfs.svc.cluster.local:8333"
s3Credentials:
accessKeyId:
name: aws-creds
key: ACCESS_KEY_ID
secretAccessKey:
name: aws-creds
key: ACCESS_SECRET_KEY
wal:
compression: gzip
data:
jobs: 2
`

Cluster definition:
`
apiVersion: postgresql.cnpg.io/v1
kind: Cluster
metadata:
name: postgresql
namespace: postgres
spec:
instances: 1
storage:
size: 2Gi

plugins:
- name: barman-cloud.cloudnative-pg.io
isWALArchiver: true
parameters:
barmanObjectName: azure-backup-store
serverName: postgresql

bootstrap:
initdb:
database: authentik
owner: authentik
secret:
name: authentik-secret

enableSuperuserAccess: true
superuserSecret:
name: pgsuperuser
`

I also tried other options, and all of them worked except for the Barman Cloud Plugin, which drops an error.

Comienza reproduciendo la configuración de ObjectStore y Cluster con SeaweedFS y, después, inspecciona el fallo de barman-cloud-wal-archive informado en la WAL Archive request. Se considera terminado cuando los archivos WAL se cargan correctamente en el destino configurado sin el error exit status 4.

Escrito por el modelo de indexación a partir del texto del issue.