Help: Site down (502) after enable admin-tools

Hi, i have enabled admin-tools with “ee admin-tools enable” and after that im getting an 502 Bad Gateway error. I tried a lot of things and nothing worked. I have disabled admin-tools. I dont know how to start debugging the error. Anyone can help? any log that would be helpful?

nmap localhost -p 9000 gives me a closed port.

Thanks in advance!