Unable to register ArcGIS Server with Web Adaptor on ArcGIS Enterprise Builder on Ubuntu

[SuryaSawant]

I am using ArcGIS Enterprise Builder 10.6 for Linux
Following are the web adaptor configurations
- OS: Ubuntu - 16.04.3
- Tomcat: version 8.0.32
- JVM: version - 1.8.0_151

- Deployed arcgis.war as server.war and portal.war to create two instances of web adaptor. 

- Note: Web adaptor is in same machine as of ArcGIS Enterprise.

I am able to access web adaptor URL's with FQDN and port 80 and 443.

Issue:

Unable to register ArcGIS Server with Web Adaptor. There is no issue in registering the web adaptor for portal.

Tried following commands:

Command - 1:
./configurebasedeployment.sh -f configurebasedeployment.properties

Output of the command - 1
==================================================
Starting the configurebasedeployment utility.
==================================================
Checking if the base ArcGIS Enterprise deployment is initialized.
The base ArcGIS Enterprise deployment is not initialized.
Validating base ArcGIS Enterprise deployment environment.
Validating Web Adaptor URLs, Server and Portal licenses and content directory path.
Configuring the base ArcGIS Enterprise deployment.
Unable to register the GIS server with the Web Adaptor. Please make sure that that the GIS server machine is running and that the account specified has administrative privileges to the site.
Failed to configure the base ArcGIS Enterprise deployment.
Stopping the configurebasedeployment utility.

Command - 2: 

./configurewebadaptor.sh -m server -w https://fqdn/server/webadaptor -g http://fqdn:6080 -u username -p password -a true 

Output of the command - 2
Unable to register the ArcGIS Server with the Web Adaptor. Please make sure that the server machine is running and that the account specified has administrative privileges to the site.

REST output of ArcGIS server Web Adaptor Properties:

{
"machineName": "***",
"machineIP": "127.0.1.1",
"webAdaptorURL": "https://***/server",
"id": "4e560475-bfe0-sdk7-866c-c690cc05fe08",
"description": "",
"httpPort": -1,
"httpsPort": 443,
"refreshServerListInterval": 1,
"reconnectServerOnFailureInterval": 1,
"isAdminEnabled": true,
"allowedOrigins": "*"
}

Note: "httpPort" is not getting configured.

Please provide suggestions for successfully configuring or similar issues faced by other users. 

[JonathanQuinn]

Do you have the JRE installed?

Configure ArcGIS Web Adaptor—ArcGIS Web Adaptor (Linux) Installation Guide (10.6) | ArcGIS Enterpris... 

Note:

In order to execute the command line utility, the Java Runtime Environment (JRE) must be present on the machine hosting the Web Adaptor. If the JRE is not present on your machine, you'll experience an error when executing the utility. See the Java SE Downloads site for instructions on how to download and install the JRE on your machine.

I can't recall the specifics, but I remember having an issue register the Web Adaptor using OpenJDK and the error message did not indicate that was the problem. When I installed Apache's JRE, I could register the Web Adaptor.

[SuryaSawant]

Thank you Jonathan. I switched from using ArcGIS Enterprise Builder to individual component installation. 
If time permits I will try your suggestion and update.  

[LouisArroyo]

Has any progress been made on this issue? I am also experiencing this problem on RHEL 7 when running the configurewebadaptor.sh script for ArcGIS Server.