EPYCD8-2T won't post with server power supply

Hey guys, I've got a strange issue where a cheapo test power supply I bought to power up my new EPYCD8-2T board while I was setting it up works just fine, but my redundant server power supply won't boot the board, it's just stuck flashing 00 on Dr Debug and fan leds flash once every second or so. IPMI does power up just fine though.

The power supply in the server is one of these t-win dual hot swap power supply things: PSU-SRA10E-Z-R
It's basically a cage which takes 2 PSM-SRA10E-Z-R power supplies.

The power supplies work just fine, as I pulled an older ATX2 based intel server board from the case and plugged in the EPYCD8-2T instead and no dice, plugging the intel board back in it works just fine.

Any tips at what to look for? I'm guessing this is a 12V power rail issue but I've tried to slightly bend the pins on the 24, 4 and 8 pin connectors to make sure they have good contact but no dice.

Is there some common thing that can cause these boards to get stuck on 00 besides a motherboard problem since it clearly works with the "test" supply.

Thanks.