A HTTP 504 error is usually caused when one server did not receive a timely response from another server in this case the MC server to your SP's server. It may well be what is causing the CU+ problem on my Explora 2A as well😡
I am getting a HTTP 504 error (Gateway Timeout) on several CU+ items tonight. I tried on different Exploras and it is always the same programs/episodes giving the error and the same ones working. After the leading ad are shown I get returned to the main screen with an error message.
Examples are My Kitchen Rules - episode 38 is working every time but episodes 39 & 40 gives the error every time I attempt to watch them (error code displayed under CU+ History). Survivor Episode 4 works but Jan Braai episode 1 gives the error. If I choose download instead on Watch then it works.
EDIT: Jan Braai is now working after about 5 attempts.
Octo-LNB to 2 x 5.2 switches. Explora1 (Prim) & HDPVR 2P (Sec), Samsung 55" UA55F8500 Smart 3D LED TV, HDMI picture & audio via Onkyo TX-NR626 receiver. Explora2 in bedroom, HDMI picture & audio to Samsung 32" UA32F5500 Smart LED TV. 100Mbps M-Web fibre (OpenServe).