Hello Lily,
Because of the replication link network is unstable, the IO timeout between the replication link.
Please check the switch and cable of the replication link.
If the problem will occur again, please collect storage logs, performance files on each controller of 2 storage arrays, and the logs of switch between the 2 storage arrays.
If we can help you with something else don’t hesitate to contact us.
Thank you for understanding.