Hello Alex,
Which version of ESXi/vSAN are you using here?
Prior to vSAN 6.6 (ESXi 6.5 U1) vSAN clusters have not only Unicast but also a Multicast requirement.
It looks like these are Unicast partitioned here so start with this.
When you configured the cluster on the 2nd/3rd page of the Wizard there is a Network connectivity check that all nodes have a vmk interface with vSAN configured and with connection - did you see this and/or what did it say?
Do you currently have a vmk interface with vSAN enabled on each hosts? (check via Web client or via CLI using: esxcli vsan network list)
Are these in the same subnet?
Does everything have/allow 1500 MTU?
Could anything be misconfigured or blocking traffic on the switch?
I see a warning in the Health check regarding Physical NIC, what does this say and/or could it be related?
Bob