My official mail-id blocked by HR manager - sent a complaint to CEO about conflict with my HR Manager

Hi Sir/Mam, I am(HR Executive) having a conflict with my HR Manager, i put mail to my CEO regarding that issue including that HR Manager in CC and he suddenly blocked my e-mail id without any information.. Is that a correct one? What can i do for this??

You need to examine the company mail policy. Whether it grants any powers to the HR Manager to do so. You can escalate your complaint to higher authorities but before that ask explanation from him for this action. You can put your differences across with the GRC to sort out your issues with the Manager.