Where and how do you handle the validationToken?

Please read this dev guide to learn more how to useRingCentral WebHooks notification.

I' sending the following parameter in header & body, If I'm wrong please correct me: -

In header

Accept : application/json

Authorization : Bearer MyAccessToken

Content-Type : application/json

In Body

Json Data =>

{

"eventFilters": [

"/restapi/v1.0/account/~/extension/~/message-store?type=SMS&direction=Inbound"

],

"deliveryMode": {

"transportType": "WebHook",

"address": "https://aabidlwc-developer-edition.ap16.force.com/services/apexrest/test/v1"

}

}

but it give me 500 error, if I miss something or doing any mistake please correct me.

Thank you