Unable to Trigger Process model From Start Process Node

Hello Everyone,

The parent process model unable to trigger the child process calling through the Start Process node. The same child process model trigger fine when trigger through the "sub process" node as synchronous/Asynchronous . Verified the parameters thrice and every thing looks good.Also Observed below error in the logs.

2022-03-04 19:02:01,035 [ajp-nio-0.0.0.0-8009-exec-358] ERROR com.appiancorp.process.engine.UnattendedJavaActivityRequest - An error occurred while executing activity: id=536873219, classname=com.appiancorp.process.runtime.activities.StartProcessSmartService2
com.appiancorp.suiteapi.process.exceptions.SmartServiceException: userMsg[error.invalidProcessModelParameters.userMsg=Unable to start specified process. Either values were not provided for required parameters or the specified process model is invalid. Process Model ID: 1552.] alertMsg[error.invalidProcessModelParameters.alertMsg=Unable to start specified process. Either values were not provided for required parameters or the specified process model is invalid. Process Model ID: 1552


Can you please help us what causing an issue?.

Thanks!!