Hi @S, Prasanna ,
Can you please check if the Hybrid Search Scenario you have implemented is Hybrid Federated Inbound Search rather than Cloud Hybrid Search? The main difference between the 2 of them is that Cloud Hybrid Search has only 1 index and your On-Premises documents are indexed within M365. On the other hand, with Federated Hybrid Search there are 2 separate indexes one for SharePoint Online and 1 for SharePoint On-Premises.
Please take a look at this article:
https://learn.microsoft.com/en-us/sharepoint/hybrid/hybrid-search-in-sharepoint
One way to tell if you're using Cloud Hybrid Search is if you're getting your On-Prem and SharePoint Online results all in one block like the image below:
Federated Hybrid Search will use 2 different results blocks for presenting results back like the image below:
If you are using Federated Hybrid Search then I believe that App Management Service is not enabled / installed in your SharePoint On-Premises installation, can you please do the following steps to confirm?
- Open SharePoint Central Administration as Administrator.
- Below “Application Management”, click on “Manage Web Applications”.
- Select your web application, and from the above ribbon, click on “Service Connections”.
If the App Management Service is not checked, check it.
Let me know it the App Management Service actually shows up, in case it doesn't you should be able to install it by following these steps:
1 Open Central Administration as administrator > Application Management > Manage Service Application.
- From the ribbon Click on New > App Management Service.
- The below dialog will be shown > Type the name of the service > Modify the DBName as you need.
- Type the name of the application pool > Select the Managed account or create a new one.
- Click OK to create an app management service.
- The app management service should be now created.
Start App Management Service Application Proxy
As above shown, the app management service application proxy is stopped, and to start it, you should do the following:
- Navigating to System Settings > Manage Services on the server.
- Find App management service > Below Action> Click on start to start the service.
- The App Managment Service should be now started.
- Go back to manage service applications.
- The App Management Service Application Proxy should now be started.
- Go to Site Settings > Below Site Actions > Select Manage site features.
- Activate "Workflows can use app permissions" feature
After all of these steps, please try running the script one more time. Let me know if any issues appear this time.
Steps above taken from: https://spgeeks.devoworx.com/app-management-shared-service-proxy-is-not-installed/