Strange behaviour - AWS EC2 instances

[Senor_Dai]

We have two deployments in AWS both running  QlikSense Aug22

One strange this we are noticing when changing instance sizes (to a larger x2iezn.2xlarge 256GB instance for example) of our AWS Dev/Test servers is even though the services are running we get this error when accessing either the hub/qmc locally or externally :

But everything works fine if we use a smaller instance eg, t3a.2xlarge (32GB) instance.

Is there anything you can think of which may be causing this and any trouble shooting tips?

Ive tried restarting the services.  Its just strange how a smaller instance works - so shows all security rules/ports are fine etc.

Thanks so much for any help.

Senor Dai

[marcus_sommer]

I don't have experiences with AWS but I could imagine that the larger instances are don't running on one node else it's more divided and now the communication between them failed - probably anything in regard to an authentication matter ...