On Friday 22nd of January 2021, we announced that there were an intermittent connection issue between the Climate Data Store (CDS) and the MARS tape archive where the seasonal forecast, ERA5-complete, ERA5.1 and UERRA datasets are stored. This resulted in many user requests failing with the error message "Failed to read 4 - Could not find a MARS database to perform request - Request failed - Some errors reported".
We are pleased to inform our users that CDS team has fixed the issue and that full access to the data has been restored.
Apologies for the inconvenience this may have caused.
Copernicus Helpdesk at ECMWF
