Using Zapier Webhooks w/ Engage Voice "JWT Missing"

It sounds like you want a Web2Campaign solution. The error you are getting is because you have not established a token yet for Engage so Engage is rejecting your request. You first need to authenticate to Engage, get an access token (JWT) and then pass that token in with your request.

Your request also looks incorrect. Since this is a new lead, I would use the lead loader to load a lead into an existing campaign. Campaigns are grouped into Dial Groups. Specifying campaign first and then group does not look right. I would just use the lead loader API here which only requires the campaign you wish to load your lead into: https://developers.ringcentral.com/engage/voice/guide/dialing/leads/bulk-import

For more examples on how to load leads into campaigns, try out the Web2Campaign blog here: https://medium.com/ringcentral-developers/ringcentral-with-automated-web2campaign-7540990ac0a9