LR Controller - SAP Diagnostic - Mediator failed to get servers topology

Hi LR Experts,

I am trying to set up LR Controller - SAP Diagnostic for CRM and ISU app servers. Mediator is my local machine where I have installed complete LR 9.5 set up (including controller). After providing SAP APP server, User Name, pwd, system and client number and trying to Validate, getting the following error

LR Controller - Validation has failed - Mediator response: Failed to get servers topology through designated server [MsgId: MMSG - 107367]

Need your help to let me know what could be the root cause?

Thanks
Deb