Error 503 when I access the webiste

Hi, I am running Ghost in development mode on FastComet hosting company. I dont know why but suddenly when i try to access my website I recieve the error

Service Unavailable
The server is temporarily unable to service your request due to maintenance downtime or capacity problems. Please try again later.

Additionally, a 503 Service Unavailable error was encountered while trying to use an ErrorDocument to handle the request.

If I do ghost restart it says that ghost is turned off, so it’ll turn on and everything come back to normal. But after some minutes the 503 error come back.

Does anyone now how can I find out the cause?