Hi,
I have very frustrating error on my ethernet, I am using example sketch for which comes with Arduino using internal clock.
Whats interesting is when I connect the ethernet I can see both the leds on ethernet jack, and the chip is getting the power, I have checked the clock signal using a scope and I can see decent 50 MHZ signal.
The board is using 8710A chip, the log of my error is given below.
E (1045) emac: Timed out waiting for PHY register 0x2 to have value 0x0007(mask 0xffff). Current value 0xffff
E (2045) emac: Timed out waiting for PHY register 0x3 to have value 0xc0f0(mask 0xfff0). Current value 0xffff
E (2045) emac: Initialise PHY device Timeout
[E][ETH.cpp:101] begin(): esp_eth_enable error: -1
Seems a common error with many boards, not just Olimex.
John
Did you follow these instructions:
https://www.olimex.com/Products/IoT/ESP32/_resources/Arudino-ESP32.txt