The API Builder needs many parameters correctly set, an example:

1. The process must exist (example for "/api/process/process1/startProcessByUser/user").
2. The process id must be correct in the POST command
3. The process "Map Participants to Users > Process Start White List" permission needs to be correctly set.
4. The "Manage API key > Domain Whitelist and IP Address Whitelist" needs a wildcard asterisk (*) to accept any IP for testing
5. The API key and API id must be the same as defined in the app.
6. Ensure firewalls/antivirus did not block the API calls.
7. You can only use the Joget DX 7 Enterprise/Pro version on API Builder.

Test using the latest Joget DX Enterprise version 7.0.32 and apibuilder_plugins-7.0.0.jar.

To the best of my knowledge my instance meets all of the above requirement for the API shown below. Does the API key come from one created in the Userview Menu of the app? Where is the key defined in the app. I see where the API Id is provided when I create it.

I am attempting to use this one:

Drag and drop the "Manage API Key" menu into your app's Userview Builder, run the userview and create the record as shown below, then copy the API Key in the datalist into your Postman/API calling program. Each app will have their own "Manage API Key" menu.

Thanks Matthew for the quick reply. However I have tried your last suggestion and still cannot connect my API Builder created API with Joget. The best I can get with a remote instance of Postman, or one right on the Windows 2019 Server on which Joget is installed, is shown below (domain obscured):

I have Joget Enterprise installed on the Windows 2019 Server as provided through AWS Marketplace. I have created the API key, as you suggest, in the Userview of my App. I have verified the API Ids over and over. I have set the authentication as Basic and verified the Authorization by verifying with the one generated by Postman. But never any different result. 

Might API Builder APIs be disabled in the AWS Enterprise version? I have used the standard JSON API call often in this application and there have been no issues. Also I have checked the log request box but cannot find any log entries when I try the calls from Postman. Thanks in advance.

I also see this set of errors in the tomcat log:

23-Sep-2022 05:37:01.470 INFO [http-nio-8080-exec-182] org.apache.coyote.http11.Http11Processor.service Error parsing HTTP request header
 Note: further occurrences of HTTP request parsing errors will be logged at DEBUG level.
    java.lang.IllegalArgumentException: Invalid character found in method name [0x160x030x010x000xe50x010x000x000xe10x030x030xd9xu0xa30x810xfa&0x14p}0xf50xd40x940x806l0x920xab0x1dFh0x8c90xa98t0x1f0x89"0xebFT ]. HTTP method names must be tokens
        at org.apache.coyote.http11.Http11InputBuffer.parseRequestLine(Http11InputBuffer.java:434)
        at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:513)
        at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
        at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:882)
        at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1647)
        at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
        at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191)
        at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659)
        at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
        at java.base/java.lang.Thread.run(Unknown Source)
23-Sep-2022 05:38:28.293 INFO [http-nio-8080-exec-191] org.apache.tomcat.util.http.Parameters.processParameters Invalid chunk starting at byte [77] and ending at byte [78] with a value of [=] ignored
 Note: further occurrences of Parameter errors will be logged at DEBUG level.

Googling the error message gives the result https://stackoverflow.com/questions/42218237/tomcat-java-lang-illegalargumentexception-invalid-character-found-in-method-na which appears to be related to a HTTPS to HTTP problem. You might want to check your web or application server for any misconfiguration in that area.