Hello, the problem is on your SAS expansion port of controller A. Unfortunately, the information you provided doesn't provide enough info to help determine exactly what. It could be as simple as a SAS cable becoming unplugged or broken somewhere in the chain or, (more likely) it could indicate a problem with your controller A module. If this unit has support/warranty on it, I would call in a support ticket. However, I am assuming you are posting here because it doesn't. I would check to ensure that all there is a SAS cable plugged into that port on Controller A and that it is fully plugged into all the shelves that are connected to the unit. If your production environment allows for a downtime, you could consider rebooting the array by using the CLI "restart" command but this will cause an outage and you should prepare your environment accordingly.
Note that I am not an HPE support representative and cannot provide you any official support. However, I'll reach out to you with a location to drop your logs in case you are interested in doing that. Have access to the complete logs may help.
Thanks
Mike