@user_3357111 hi!
The ES5D21VST000 stack card is not supported on your S5730-48C-PWR-SI-AC with the current software version (V200R011). You need to upgrade to V200R012 or V200R013.
Below are the devices that support the ES5D21VST000 stack card with V200R012 (Please see " Card Overview" tab):
http://support.huawei.com/hedex/ ... 5252Bwith%25252B2*QSFP%25252B%25252BInterface%25252529&lang=en
Below are the devices that support the ES5D21VST000 stack card with V200R013 (Please see " Card Overview" tab):
http://support.huawei.com/hedex/ ... 5252Bwith%25252B2*QSFP%25252B%25252BInterface%25252529&lang=en