@Hejran, Can you elaborate on what you mean by losing the vSAN configuration? e.g. did you mean you lost vCenter? (this shouldn't matter).
So, you have created a new cluster with a new vsanDatastore - vSAN clusters have a 1:1 relationship with their vsanDatastore and while you can still access the original namespaces and the data Objects are intact, the pathing to these is the problem. The Objects descriptors are trying to be accessed at /vmfs/volumes/vsan:1234/namespace/ (the old vsanDatastore location) but where they are looking is the only vsanDatastore they have available e.g. /vmfs/volumes/vsan:5678/namespace/ which doesn't exist.
The simple solution to this is to rejoin all nodes to the original cluster, however, to be able to do this requires knowing the Sub-Cluster UUID - do you have any log bundles ever collected from any of these nodes from before re-install or have LogInsight/Splunk/other Syslog/collector configured? While this can be retrieved from numerous locations, vsansystem.log is probably the best bet (isn't very busy and thus less rollover). If you can't get this UUID (and I am unaware if it is possible to get these off disk metadata etc. ) then the alternative would be to change the Object lookup path of every Object in this cluster to the new vsanDatastore path or repoint them via other means.
