I have a production replica set that went down for 3-4 minutes, apparently because the Primary could not connect to one of the Secondaries. I'm having a hard time understanding why the Primary kept stepping down and up.

I've been managing this replica set for 3 years and have never seen this happen.

Here's the replica set structure:

PRIMARY: m4.mydomain.com (104.167.32.55) - Priority 10
SECONDARY: m2.mydomain.com (162.221.2.98) - Priority 5
SECONDARY: m1.mydomain.com (40.113.11.54) - Priority 1

The log for the period is attached.