ESP32-POE-ISO ETH port not coming online (Timed out waiting for PHY register..)

[bilatex]

Hi,
when enabling the Ehternet port on the ESP32-POE-ISO board, I receive the following error:
Timed out waiting for PHY register 0x2 to have value 0x0007(mask 0xffff). Current value 0x0000
Timed out waiting for PHY register 0x3 to have value 0x0007(mask 0xc0f0). Current value 0x0000
Initialise PHY device Timeout
Ethernet init failed
MGOS init failed: -32
Unmounting filesystems
Restarting
(and we are in a boot loop)

I use mongoose-os with this settings for the ethernet port: mdc:23, mdio:18, power:12 address:0  (tried different setting, power -1 address 1, ... but same error)

setting up the board using wifi is no problem, only when enabling ethernet the board is in a boot loop.

Does anyone had this problem before?
Thanks a lot