The user who normally uses Automation studio asked me for help and says it is happening for both live and test. I have not been that closely involved in the setup etc.
Is this when accessing via Kinetic itself? ie. the embedded experience. and does the customer have multiple App servers?
I believe i have seen this or something similar when registering the instance on APP02 and then trying to access it via Kinetic via APP01. The solution was to update the Frame ancestors for the environment via the Integration portal to have both or more FQDNs in there.
Alternatively you could try reconnecting the instance via the integration portal > Instances tab to ensure the details are correct.