Unable to initiate selective backup through pbm and pbm-agent in EC2 using Percona MongoDB v5 binaries

Hello,
When I attempt to run a selected backup of a test database and collection I get an error as follows after installing a the percona backup tools on the hidden, zero-priority, non voting mongo replica that we use for EBS snapshotting :

pbm backup --compression=gzip --ns=testDB.testCollection

results in error:
Error: backup pre-check: no available agent(s) on replsets: replicaSetName

System details:
Host replicas:
OS: Amazon Linux 2:
Installed Percona RPMS;
percona-server-mongodb-shell-5.0.17-14.el7.x86_64
percona-server-mongodb-mongos-5.0.17-14.el7.x86_64
percona-backup-mongodb-2.3.0-1.el7.x86_64
percona-server-mongodb-server-5.0.17-14.el7.x86_64
percona-server-mongodb-debuginfo-5.0.17-14.el7.x86_64
percona-server-mongodb-5.0.17-14.el7.x86_64
percona-mongodb-mongosh-1.8.1-1.el7.x86_64
percona-server-mongodb-tools-5.0.17-14.el7.x86_64

PBM software:
percona-backup-mongodb-2.3.0-1.el7.x86_64

============================
pbm status output

Cluster:

replicaSetName:

  • replicaSetName/mongodb-01.some-domain.com:27017 [S]: pbm-agent NOT FOUND FAILED status:
  • replicaSetName/mongodb-02.some-domain.com:27017 [P]: pbm-agent NOT FOUND FAILED status:
  • replicaSetName/mongodb-03.some-domain.com:27017 [!Arbiter]: arbiter node is not supported
  • replicaSetName/mongodb-bak.some-domain.com:27017 [S]: pbm-agent v2.3.0 OK

PITR incremental backup:

Status [OFF]

Currently running:

(none)

Backups:

S3 us-east-1 s3://uniquename-percona-mongodb-backups/my/backup/path (none)

The replica node with the Percona backup software on it is in a healthy and current SECONDARY as far as MongoDB is concerned. and tcp connectivity to port 27017 is there.