XMP and a full memory board

[comuscomp]

Hi
B550 Aorus pro ac
64 Gb DDR4 (4 x 16 Gb) HyperX
Ryzen 5 3600.

I have a strange problem, if I install 2 sticks of ram rated 3200 in A2 B2 and set XMP to profile 1 the machine fires fine.
if I change the ram sticks for a second pair again set to profile 1 the machine fires away. But if I install all 4 sticks and set profile 1 the machine won't even POST.
If I disable XMP with all 4 sticks it works fine but the memory speed shows 2400.
Is there a problem with the board

[shadowsports]

Greetings,
Is the memory listed on the QVL for your board?

XMP profiles have specific requirements.  You don't have to use them, but they can be helpful.  If the board boots with the XMP profile and detects the RAM at 2400 (SPD), you may need to set timing and voltage manually for the RAM to operate at or near full speed.

[comuscomp]

With  2 sticks the XMP rates the memory at 3200 as profile 1. with 4 sticks it won't start at all with XMP activated.
the memory packaging has a sticker on it that states XMP Certified and it is in the recommended memory list.