In pca client

this.pca = new PublicClientApplication({
      auth: {
        clientId: process.env.CLIENT_ID,
        authority: `https://login.microsoftonline.com/${process.env.TENANT_ID}`,
        clientSecret: "xxx"
      },
    });

You need to add a client secret generated from the app registration in the AD.

1. Navigate to the app registration in the Azure portal.

Copy the value, not the secret ID, and replace it in the configuration.