Mongodb won't start after adding 2nd net option to mongod.conf file

Question

I try to add another net with the its corresponding bind ip and port to my AMI ec2 mongod.conf file so I will be able to create a 2 node replica set but when I run the command "sudo service mongos restart", mongos won't start. Here is my mongos.conf file:

# mongod.conf

# for documentation of all options, see:
#   http://docs.mongodb.org/manual/reference/configuration-options/

# where to write logging data.
systemLog:
  destination: file
  logAppend: true
  path: /var/log/mongodb/mongod.log

# Where and how to store data.
storage:
  dbPath: /var/lib/mongo
  journal:
    enabled: true
#  engine:
#  mmapv1:
#  wiredTiger:

# how the process runs
processManagement:
  fork: true  # fork and run in background
  pidFilePath: /var/run/mongodb/mongod.pid  # location of pidfile
  timeZoneInfo: /usr/share/zoneinfo

# network interfaces
net:
  port: 27017
  bindIp: 172.31.90.193 # Enter 0.0.0.0,:: to bind to all IPv4 and IPv6 addresses or, alternatively, use the net.bindIpAll setting.
net:
  port: 27017
  bindIp: 172.31.92.31
#security:

#operationProfiling:

replication:
 replSetName: "Midterm"

#sharding:

## Enterprise-Only Options

#auditLog:

#snmp:

Does anyone know why this is happening? I tried doing this in a vm using vagrant and it worked. Why would be any different in AMI ec2?

**UPDATE:

This is what the security group of one of my instances looks like: