PSA Upgrade: 7.53 -> 7.54 Fails

[kitchen]

I've tried upgrading my installation of plesk from 7.53 to 7.54 and I receive the following message:
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21. Downloading http://autoinstall.plesk.com//PSA_7...api-rpc-7.5.4-fc2.build75050930.11.noarch.rpm (8 files to go)

File download failed.
Empty reply from server
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Anyone have any ideas?

muchos gracias!