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.
I have the same issue, several of the items in my NCM tested OK and then ran but when they try to do the daily jobs they fail to log in, and i am baffled as to why. The thing is we don't use one Cisco UN and PW for all devices. So it seems as long as the last one i test and set is the same UN and PW as a different switch, router, or ASA, then i am OK. But if not, well, Epic fail day after day after day.