Certificate based authentication works in console app , hangs in MVC

[RSCA001]

The code to build a client context ( ctx) object with a certificate is :

ctx = new PnP.Framework.AuthenticationManager(AzureAppId, X509certificate, tennantid, null, PnP.Framework.AzureEnvironment.Production, null).GetContext(SharePointURL);

This works fine in a console app, but hangs when in a MVC app. Does anyone know why, and how to fix it ?