Reboot system ESP8266

[BorgMcz]

Good day,
i am trying to use your library with ethernet3 (Wiznet W5500 and ESP8266). Unfortunately, after adding your library to the sketch, it will start restarting at startup. Do you have any idea what could be wrong?
15:33:15.144 -> ets Jan 8 2013,rst cause:2, boot mode:(3,6) 15:33:15.144 -> 15:33:15.144 -> load 0x4010f000, len 3656, room 16 15:33:15.144 -> tail 8 15:33:15.144 -> chksum 0x0c 15:33:15.144 -> csum 0x0c 15:33:15.144 -> v9c56ed1f 15:33:15.144 -> ~ld

Thank you.