The AA or QR forums would be better choices I think. As this is an AA ticket I would start in the AA forum; when an airline cancels or loads a new flight it often takes some time for codeshares to be reattached or made available. I would give it a few days and see if the codeshares for this new flight number are reestablished. See for example:
What are my rebooking options for a cancelled codeshare flight

Qatar takes back 3rd DOH-JFK frequency previously operated by AA