MongoDB ReplicaSet without any Primary

I have 5 node replicaset. where host-0 is the primary, host 1 to 4 are secondary.
I made the host-4 & host-4 down for some maintenance work.

The rs.status() was look like :

host-0 -> primary
host-1, host-2 -> secondary
host-3, host-4 -> not reachable/healthy

Then my rs-2 pod gets down for a connection issue, & after that I see there is no primary in the replicaset. Even the previous primary host-0 converts to secondary !!
I have no idea why.

Here are the member found from rs.status() output