I'm trying to run a series of circuits in a job and I keep getting this error message which I haven't been able to find the meaning of anywhere in qiskit's documentation, online, etc. The job appears to run for 15 minutes and only then does an error appear... Anyone have any clue as to what this could be? The job consists of batches of circuits where each batch is just a certain circuit repeated a different number of times (before measurement), so I don't see any obvious reason why the circuits from one batch work fine but not from another.
The list of API error codes is here: https://quantum-computing.ibm.com/lab/docs/iql/manage/errors
9999, the answer is not very satisfying:
Contact IBM Quantum via Slack for help.
Once there, checkout out the channel
In my experience, it is usually a temporary problem and you can try again later. But the "something went wrong" description is not very useful.
It means there is an error internally in the IBMQ system, but the exact error has not been seen before and therefore does not have its own error code (yet). I have run into a large number of these errors. Usually, a reasonable rule of thumb seems to be that the more circuits are in the job the more likely it is for the job to return a
9999 error. Usually, although not always, re-executing the circuit works.