In case the Post Configuration (msdyn_postconfig) and Post Rule Configuration (msdyn_postruleconfig) are missing in your Sales Hub SiteMap, here’s how you can add them somewhere in the Settings area in the SiteMap –

Like this, the Post entities don’t exist by default in the expected App Settings area and in fact are present in the default classic Settings are in Dynamics 365 CRM

Add Entities to the App

First, you’ll need to add the Entities to the Sales Hub app since they don’t appear by default –

1. In editing Components in the App, search for the Post Configuration (msdyn_postconfig) and Post Rule Configuration (msdyn_postruleconfig) –
   Tick them and then Save so that you can later add them to SiteMap.
   Add the Post Configuration (msdyn_postconfig) entity.
   
   
   And Post Rule Configuration (msdyn_postruleconfig)
   
   
2. Once both of them have been checked, Save and then add them to the Settings area. Probably create a new Area and then add these 2 entities in them.
   
   
3. Save and Publish the SiteMap changes too and refresh the Sales Hub App.
   

Hope this was useful!

Here are some Power Automate posts you want to check out –

1. Blocking Attachment Extensions in Dynamics 365 CRM
2. Upgrade Dataverse for Teams Environment to Dataverse Environment
3. Showing Sandbox or Non Production Apps in Power App mobile app
4. Create a Power Apps Per User Plan Trial | Dataverse environment
5. Install On-Premise Gateway from Power Automate or Power Apps | Power Platform
6. Co-presence in Power Automate | Multiple users working on a Flow
7. Search Rows (preview) Action in Dataverse connector in a Flow | Power Automate
8. Suppress Workflow Header Information while sending back HTTP Response in a Flow | Power Automate
9. Call a Flow from Canvas Power App and get back response | Power Platform\
10. FetchXML Aggregation in a Flow using CDS (Current Environment) connector | Power Automate
11. Parsing Outputs of a List Rows action using Parse JSON in a Flow | Common Data Service (CE) connector
12. Asynchronous HTTP Response from a Flow | Power Automate
13. Validate JSON Schema for HTTP Request trigger in a Flow and send Response | Power Automate
14. Converting JSON to XML and XML to JSON in a Flow | Power Automate

Thank you!