No connection could be made because the target machine actively refused it (openPDC and openHistorian)

Dear Sir,

I am able to connect to a virtual PMU using a PMUConnectionTester and save the configuration file, but when I try to add the PMU connection configuration file to openHistorian or openPDC and click on request configuration, I get the following errors.

I checked the openhistorian console, and it shows the following error.

I checked that the openhistorian service was running in the background.

Earlier everything was working seamlessly, its only recently I am getting the above errors.

P.S. I am only getting this error on a single PC, whereas with other PC everything is working fine. May I know how to debug this error. I will be thankful for the help.