No usable signal found, it is possible clustering has failed

[miseq_user]

My most recent MiSeq (Nano v2) run failed with the following error: No usable signal found, it is possible clustering has failed.
I had a look at the focus images and there are clusters (see attached images). Cluster density is low, but comparable to previous runs that have finished without errors. Any idea what could be the problem?

[gregrds]

Hello miseq_user

How diverse is the library and is there PhiX in the run? Is the cluster density comparable to previous runs on the MiSeq? Is there a chance you're comparing cluster densities on patterned v nonpatterned flow cells?