AWS probe is not displaying all EC2 instances.
Specifically, EC2 instances in the following regions are not displayed:
EU (London) - eu-west-2
US East (Ohio) - us-east-2
Canada (Central) - ca-central-1
The 5.26 probe version doesn't contain all the regions as we intended to begin supporting these newer regions in version 5.31 of the probe which is due out at the end of July 2017.
AWS EC2 monitored with AWS probe v5.26
As a workaround to make this work in the current version, edit the aws.cfg and look for the <Regions> section. At the end of that section, append the following:
name=EU (London) Region
name=US East (Ohio) Region
name=Canada (Central) Region
Restart the probe after this, and it should be able to discover the EC2 instances in those regions.