Hello.

Unfortunately this is the least descriptive error possible - E_FAIL can be just about anything. We do not actually create this error anywhere directly in our code, but it can come from functions that we are calling, or from a COM infrastructure.

I can only suggest to do some "related" experiments, and try to collect some knowledge in this way, which can then help us to get closer to the cause of the problem. Such as (pick as many as possible):

1. Is this only with specific node, or with any node?
2. Are you able to call other operations on the server from your VB6 program, such as Browse? If not, what is the error?
3. Can the node be read using the "COM" demo app that comes with QuickOPC? If not, what is the error?
4. Do the VB6 examples (that connect to our demo server) work? If not, what is the error?
5. Can the node be read using the .NET-based demo app that comes with QuickOPC? If not, what is the error?
6. Can you modify the VBScript example for "ReadValue" that comes with QuickOPC, and see if it can be used to read your node? If not, what is the error?
7. If you modify your program to connect to our public demo server (as in QuickOPC examples) and read a node from it, does it work? If not, what is the error?

Best regards