The network status LED doesn't light

[Flora_Yealink]

In this scenario , it seems the base doesn't obtain the network and there is no handset registered to the base.
you mentioned " just the power light turns on but other lights are off " ,may i know after you do the factory default ,what is the status of the network indicator ? if the network indicator won’t light up solidly but flashes continually, it means that the W52P can’t get an IP address ,in this case, would you please try to check if you can register the handset to the base and configure the static IP address for it ? and make sure the network cable can work well .

If it still can't work it maybe the hardware issue, please contact your vendor or local distributor and send the problem description for help.
If you can't get a support from them, please send an email which include problem description, test result, your country, phone SN number to Support@yealink.com

If only power light turn on , but the network ligth is off , maybe hardware issue.

and during the hard reset process, did all the three lights trun on one by one or only the power light turn on durning the whole process? only one power light turn on during the whole process, maybe the hardware issue .