The Publish to web option is unavailable.
The option to Publish an embedded code to the web may not be enabled on your Tenant. You may not have the required permissions to enable it.
- Go to Settings.
- Click on the Admin portal.
- Expand Tenant settings.
- Navigate to Publish to web under Export and Sharing.
- Enable Allow existing and new codes.
- Click on Apply.
Once applied, these changes can take up to 15 minutes to come into effect.
See the official Microsoft documentation here: https://docs.microsoft.com/en-us/power-bi/admin/service-admin-portal#publish-to-web.