"Suddenly" I can't get updates anymore - Any hints?

Hello,
After a while it seems I can't get updates anymore:

# yum update
Loaded plugins: refresh-packagekit, security
ol6_latest/primary                                                                                                        |  19 MB     00:03    
http://public-yum.oracle.com/repo/OracleLinux/OL6/latest/x86_64/repodata/primary.xml.gz: [Errno -1] Metadata file does not match checksum
Trying other mirror.
Error: failure: repodata/primary.xml.gz from ol6_latest: [Errno 256] No more mirrors to try.

Can I recover from this? How?

Thanks in advance,
Carlos.