Golang - Spaces - noSuchBucket Error for copyObject bucket while putObject with the same bucket works

Hello,

I am trying to make a copy of a file in Spaces

If putting in a new file with

bucket := "someBucket"

object := s3.PutObjectInput{
  	Bucket:      aws.String(bucket),
	Key:         aws.String(key),
        ...
	}

it works, but if copying

bucket := "someBucket"

cpObj := s3.CopyObjectInput{
		Bucket:     aws.String(bucket),
		CopySource: aws.String(fromPath),
		Key:        aws.String(toPath),
	}

_, err := cl.CopyObject(&cpObj)
log.Println("Error", err)

it logs:

Error NoSuchBucket

It does not make any sense to me. Any help appreciated. :)

Mila