Following Michael’s advice in the above post, I commented out a plug-in in the app.yml file that was from an initial attempt at SSO authentication using the VK plug-in (we never went with this implementation but obviously forgot to remove the plug-in from the app.yml file).
## Plugins go here
## see https://meta.discourse.org/t/19157 for details
hooks:
after_code:
- exec:
cd: $home/plugins
cmd:
- git clone https://github.com/discourse/docker_manager.git
## - git clone https://github.com/discourse/discourse-vk-auth.git
After commenting out the line above I ran sudo ./launcher rebuild app again. After the rebuild the forum site appears to be up and running (testing now).
Thanks again for everyone who took the time to review my posts and comment. Your help was very much appreciated (what better way to spend a the Thanksgiving holiday here in US 
).
Stay safe.