I have WS-C2960+48PST-L switches that NCM is not able to login to currently. I am able to login via SSH via putty with the same credentials. I found this article https://support.solarwinds.com/Success_Center/Network_Configuration_Manager_%28NCM%29/NCM_Error%3A_Connection_Refused_by_A.B.C.D but none of these steps worked. I am running NCM 7.4.1.