The cipherList option has not been set properly

The remote mount failure, due to invalid value of cipherList, leads the error messages and the courses of action that you can take to resolve the issue.

Another reason for remote mount to fail is if cipherList is not set to a valid value. A mount command would fail with messages similar to this:
6027-510 Cannot mount /dev/dqfs1 on /dqfs1: A remote host is not available.
The GPFS log would contain messages similar to this:
Wed Jul 18 16:11:20.496 2007: Command: mount remote.cluster:fs3 655494
Wed Jul 18 16:11:20.497 2007: Waiting to join remote cluster remote.cluster
Wed Jul 18 16:11:20.997 2007: Remote mounts are not enabled within this cluster. \
See the Advanced Administration Guide for instructions. In particular ensure keys have been \
generated and a cipherlist has been set.
Wed Jul 18 16:11:20.998 2007: A node join was rejected.  This could be due to
incompatible daemon versions, failure to find the node
in the configuration database, or no configuration manager found.
Wed Jul 18 16:11:20.999 2007: Failed to join remote cluster remote.cluster
Wed Jul 18 16:11:20.998 2007: Command: err 693: mount remote.cluster:fs3 655494
Wed Jul 18 16:11:20.999 2007: Message failed because the destination node refused the connection.

The mmchconfig cipherlist=AUTHONLY command must be run on both the cluster that owns and controls the file system, and the cluster that is attempting to mount the file system.