The Input LED indicator of the PSU shows a green light (normal behaviour) but the Output LED of the PSU shows a red light (error warning).
Although the PSU is designed specifically for S5700, it supports POE. Because the switch model does not support poe (no "PWR" in the name) the PSU cannot be registered on the device. To fix this i needed to replace the PSU with one that does not support POE. The available model for the S5700-52C-EI are the following:
To find the root cause of this issue i needed to check the switch and PSU type and see if they are compatible.
Always check the device exact model (with regards to POE support) when installing a new PSU.