Add service account as a site owner

Step 1: Go to the URL below to add the Service Account as an owner of your Google Search Console property.

https://www.google.com/webmasters/tools/home

Step 2: Go to Settings > Users and permissions > Add User

Step 3: A popup will appear. In that enter the Service Account ID (copied while creating the service account) in the Email address field. In the Permission field select Owner and then click Add. Your service account has ownership rights now.