Access point

How do I tell if an access point is going bad? Or the POE that's powering
it?

Intermittently, people will tell me the wireless keeps knocking them off.
Then it comes back. Then gone. Then back, etc.

This is the result of a ping to the IP address of the access point:

Pinging 192.168.0.252 with 32 bytes of data:
Reply from 192.168.0.158: Destination host unreachable.
Reply from 192.168.0.158: Destination host unreachable.
Reply from 192.168.0.252: bytes=32 time=4ms TTL=64
Reply from 192.168.0.252: bytes=32 time=1ms TTL=64

Note that the first 2 replies are from a different IP address. Never seen
that before. Makes me wonder if there's a IP address conflict. I've done
at least a dozen pings since then and that issue has not happened again.

Thanks.