Resolve the Email cannot be saved to object type issue in the Sidebar

This issue concerns the permissions configured for specific object types in Salesforce. It manifests with the inability to save email messages or calendar items to specific Salesforce objects and the following notification in the Sidebar:

Email cannot be saved to [object type]

To resolve the issue:

1. Log in to Salesforce Lightning Experience

2. Click on the Gear ⚙ icon and select Setup

3. In the Quick Search field, enter “Custom Objects” to quickly find and open the necessary setting

4. Find the object in question on the list

5. Click Edit

6. Under Optional Features, enable the Allow Activities checkbox

7. Save the changes

8. Open your Sidebar customization and click Save to enforce the Salesforce changes to RGES

9. Go to the Sidebar, open the menu and click Refresh

After taking these steps, you should be able to save email messages and calendar items to the necessary objects as expected.