Validation is not working

"submit" buttons aren't really valid in an interface used directly as a Site page, as there's nothing to "submit" since there is no Task / process instance.  What are you "submitting" here?

Additionally: it appears as if you have no need for the "validationGroup" parameter.  I would suggest just removing that (unless you already know you require it for reasons outside of the portions of code/screenshots you've included here).  This allows the built-in "required" field indicator to show up in the first place (which has always been a silly side-effect of using this feature).  Honestly I almost never use validation groups since the way it works is finnicky and counterintuitive.  But your primary issue here is probably that you're trying to "submit" stuff while not in a Task.

Thanks for the reply. I have used a!startProcess at the Button's saveInto like this:

saveInto: {
   a!startProcess(
     processModel: cons!NGS_PM_TEST,
     processParameters: {},
     onSuccess: {}
   )
}

But still validation is not working.

In this case you would not need to set "submit" to true (in fact you should probably set it to FALSE); keep the "validate" parameter set to true; and i still suggest you remove the "validation group" parameter altogether, as i mentioned before.

Thank you very much.

As per your suggestion I have changed the property value and it works.

Thank you very much.

As per your suggestion I have changed the property value and it works.