Unable to upgrade agents in Additional Polling Engine (APE) after upgrading to SolarWinds Platform 2023.4 and above

From the affected additional polling engine server, you might notice that both Recommendations and the Orion Module Engine services are stopped and will only run for a few minutes before it stops again.

In the Recommendations log, you will see similar errors that points to SWIS like this:

[SolarWindsRecommendations.OnStart] ERROR SolarWinds.Recommendations.ServiceContainer.ServiceHelper - Connection retry count to Local SwisV3 exceeded.
[SolarWindsRecommendations.OnStart] FATAL SolarWinds.Recommendations.Service.RecommendationsService - Starting RecommendationsService failed
[SolarWindsRecommendations.OnStart] INFO SolarWinds.Recommendations.Service.RecommendationsService - Stopping RecommendationsService because of FATAL failure during startup

In the C:\ProgramData\SolarWinds\InformationService\v3.0\Orion.InformationService logs, you will notice that it is trying to use a certificate other than SolarWinds-Orion:

[9] INFO SolarWinds.InformationService.Core.InformationServiceService - (null) (null) No sslcert http configuration for endpoint 0.0.0.0:17774 exists. Creating a new one. System.IO.FileNotFoundException: No SSL Certificate configuration for IP Endpoint 0.0.0.0:17774 could be found. ---> System.ComponentModel.Win32Exception (0x80004005): The system cannot find the file specified

1. In http://OrionHostname/Orion/admin/AdvancedConfiguration/global.aspx, Set the following back to default:
   • CertificateNameForSafeguardCommunicationOnSwisRestEndpoint
   • DisableSwisRestEndpointOnPort17778
2. The Swis.RestEndpoint should look like this:
   • 
3. Hit SAVE
4. Restart all Orion services from main and additional polling engine/web servers.