I have exactly the same scenario, PC (while IP Phone booting) two times authenticating normally as needed, but the last third attempt it's not. In a logs for dot1x on a swiches it says that "no response from client". Seems that Phone do not pass EoL ...
Hi wkamil123, Recently I have had the same issue with the same IP Phone model. Could you tell if you solved the problem or maybe you used some workaround.I will be really appresiate if you give some information. Thank you