I've had this problem starting just this week. Everything seems fine, and I know the app is indeed connected to SQL Server because intellisense picks up the name of the parameter the SP requires. But I get the "Resource not found" error.

I did notice that it's listing the connection differently. Before -- and those older apps are working fine -- it showed as the SQL database name, but now it shows as SQL Server: the call used to be to DatabaseName.schemaspname, but now it's SQLServer.schemaspname. So something appears to have changed lately, and that change seems to have broken something. (I tried changing the same of the data connection to the database name rather than SQLServer, without luck.)