Recently applied SP3 and getting this error when bringing up the Portal
DevTest 10.7.2 with SP3
MongoDB services deployed to VSE caused this error.
These steps resolved the issue:
1. Log out of the Portal Service.
2. Stop both the Registry and Portal services.
3. Add the below property in the RegistryService.vmoptions and PortalService.vmoptions files.
-Dmanagement.metrics.mongo.connectionpool.enabled=false
4. Start the Registry and Portal Services.
5. Deploy the MongoDB services.
Portal displayed all services, including the MongoDB services with no issues.