ERROR: Cannot locate specified Dockerfile: Dockerfile

[firegbn]

Buen dia,
Cuando correo ./start me aparece que no a encontrado el Docker file

elcome to The Threat Hunting Environment

.env file exists...ok
[+] Good. ./external/certs/thethe.crt exists.
[+] Good. ./external/certs/thethe.key exists.
Building celery
ERROR: Cannot locate specified Dockerfile: Dockerfile

Gracias