We have been informed by the Climate Data Store that there are technical issues affecting access to the CMIP5 data. Some requests may unfortunately randomly fail.
The Climate Data Store is actively working with the CMIP5 data provider to restore full access to the data as soon as possible.
We will update this post as soon as we will have more information.
We are sorry for the inconvenience this is causing.
Regards,
User Services at ECMWF