The powerline set I have (TL-WPA4220) started dropping internet speed when connected at a distant power outlet (it was working OK before). It only affects download speeds, which go from 24Mbps to 1.17Mbps! The upload speed remains the same, at 4.68Mbps

The system used to work fine before, so it is probably in the same phase. 

Using tpPLC app I see a connection of 219 Mbps. If there were on a different phase, shouldn’t this also affect the connectivity shown on tpPLC? I have tried to pair using in the other outlets of the same floor, but they don’t pair, so I assume if they only pair on this outlet, this would be the one in the same phase (there are three phases on each floor).

Also, how come there is no speed penalty in the upload (4.6 Mbps), but the download drops from 26 to 1.1 Mbps?