Csla based application and "SSL/TLS"

[Chicagoan2016]

Almost all of our Csla projects hit an address verification service provided by Melissa Data.
One application starting throwing this exception "The request was aborted: Could not create SSL/TLS secure channel.” when trying to connect to Melissa data web service.
The strange thing is that the code that calls the web service (Melissa data) is the same across all projects (essentially copied/pasted between projects) but only one application is throwing this exception and even this application was working up until last week : )

Anyone of us have experienced such behavior?
Kind Regards

[ossendorf-at-hoelscher]

Any updates (OS, dotnet) or use of now outdated cipher suites?

[Chicagoan2016]

Just one application is throwing the exception. I am debugging other applications on the same machine and they are working fine