Assuming that you have valid accession IDs (e.g., check the SRA website to confirm), the problem is most likely a transient connection or server-side issue. You can try again later to see if you have success.
I think you are maybe working with @SoilRotifer (I assume so because he reported the same error message in a direct message). In that case, we confirmed that was a transient issue and I think he got it working in the end.