UNREACHABLE! Failed to connect to the host via ssh

[bluefire100]

My ssh connection with remote server works fine after I copied the public key to the new Streisand server in order for authentication via keys. Login works without password.
ssh root@myserverIP

Expected behavior:

Finishing install script without connecting error

Actual Behavior:

At the very end of installation I got this error message
--> fatal: [myserverIP]: UNREACHABLE! => {"changed": false, "msg": "Failed to connect to the host via ssh: Permission denied (publickey,password).", "unreachable": true}

Steps to Reproduce:

[ contents of streisand-diagnostics.md here ]
none

Additional Details:

Log output from Ansible or other relevant services (link to Gist for longer output):

Target Cloud Provider: No cloud provider - own server

Operating System of target host: Ubuntu 16.04 LTS

Operating System of client: Mac OS

Version of Ansible, using ansible --version : ansible 2.9.16

Output from git rev-parse HEAD in your Streisand directory : none