Hi,
I think the issue is that you have not generated a SimBrief flight plan on your account since July 16th. It’s likely your flight data is no longer available and therefore can’t be loaded by the A320. Please generate a new flight plan (or re-generate your previous flight) and try loading it into the A320 again.
Normally if you enter your Navigraph username “BrzIBrzI” it should work. But if you still need your SimBrief ID, it can be found on the New Flight page:
Hope this helps,