add UI nuance to troubleshooting section

Author: muhammadatifjav

src/connections/sources/catalog/cloud-apps/sendgrid/index.md

@@ -89,10 +89,20 @@ Collections are the groupings of resources Segment pulls from your source. In yo
 
 ## Troubleshooting
 
+### Invalid Credentials Error
+
 If you're getting an "Invalid Credentials" error when setting up the SendGrid source, send a direct ping to the [SendGrid Marketing Campaigns API](https://sendgrid.com/docs/API_Reference/Web_API_v3/Marketing_Campaigns/campaigns.html){:target="_blank”} to test if you're using the correct credentials.
 
 Make sure you allowlist Segment IP addresses on SendGrid. [Contact Segment](https://segment.com/help/contact/){:target="_blank”} for the list of IP addresses to allowlist.
 
+### Configuring Webhook
+
 When you disable your SendGrid source, you'll need to also disable the webhook portion of your configuration.
 
 If you are only able to create one webhook, review your SendGrid [account plan details](https://sendgrid.com/en-us/pricing). On the Sendgrid free plan, you can only have 1 webhook.
+
+### Zero data or Partial Data Synced
+
+If you haven't subscribed to SendGrid’s marketing campaigns features, then the object collections will not be synced. As a result, you will see “Zero data synced” in your runs on Source Overview page. Moreover, if you have only selected a few objects to be synced, then only those objects will sync and show up in the Source Overview. 
+
+However, in both cases, the webhook still processes events data and syncs it to the warehouse. To view the data synced to the warehouse and sync history, navigate to the 'Connections > Destinations', select the relevant Warehouse Destination and then select the Source schema.