SpringBoot fails to deploy after adding .ebextensions for ngingx SSL -[An error occurred during execution of command [app-deploy]]

I have a SpringBoot app that deploys just fine to AWS Beanstalk, and the default nginx proxy works, allowing me to connect via port 80.

Following the instructions here: https://docs.aws.amazon.com/elasticbeanstalk/latest/dg/https-singleinstance.html, and verifying with another of my projects that works with this exact config, Beanstalk fails to deploy the app with error:

2020/05/29 01:27:56.418780 [ERROR] An error occurred during execution of command [app-deploy] - [CheckProcfileForJavaApplication]. Stop running the command. Error: there is no Procfile and no .jar file at root level of your source bundle

The contents of my war file are as such:

app.war
    -.ebextensions
        -nginx/conf.d/https.conf
        -https-instance-single.config
        -https-instance.config
    -web-inf/

My config files pass as valid yaml files. (These files are identical to those in the AWS doc, and those that work in other project on mine.)

I am using a single instance, with port 443 set open.

These are the errors reported throughout the various log files:

----------------------------------------
/var/log/eb-engine.log
----------------------------------------
2020/05/29 01:37:53.054366 [ERROR] /usr/bin/id: healthd: no such user
...
2020/05/29 01:37:53.254965 [ERROR] Created symlink from /etc/systemd/system/multi-user.target.wants/healthd.service to /etc/systemd/system/healthd.service.
...
2020/05/29 01:37:53.732794 [ERROR] Created symlink from /etc/systemd/system/multi-user.target.wants/cfn-hup.service to /etc/systemd/system/cfn-hup.service.


----------------------------------------
/var/log/cfn-hup.log
----------------------------------------
ReadTimeout: HTTPSConnectionPool(host='sqs.us-east-1.amazonaws.com', port=443): Read timed out. (read timeout=23)

Issue with Java and Linux version

If you are using Java 8 and Linux 2.10.9 code will work and override ngingx configuration but if you choose Corretto 11 and Linux 2.2.3 get following error.

Error: there is no Procfile and no .jar file at root level of your source bundle

Create new environment with Java 8 and deploy app again will resolve issue.