How many groups and users are you trying to import from AD? Have you taken a look at the Powershell connector logs to see if it’s finding objects? You can find info on viewing the logs on the following page https://docs.openiam.com/docs-126.96.36.199/connectorconfig/microsoft/2-powershellconnectorsusage
If your logs show that it finds users and groups it maybe a connection issue with rabbitMQ. More likely a timeout issue with OpenIAM not waiting long enough for the response.