Error: state manager failed on NFSv4 server foo with error 13

Hi all,

I've recently upgraded nfs mounts from nfs3 to nfs4 and now I often have:

Error: state manager failed on NFSv4 server foo with error 13

in logs. Error 13 is NFS4ERR_ACCESS Permission denied: The caller does not have the correct permission to perform the requested operation.

Client machines run Debian Lenny. I don't use Kerberos. Could you give me suggestions on how to debug this issue or resolve it.

Thanks,
Vedran