Without log, we can't tell what's wrong where. Also the advantage of this knowledge base portal is, you can search this whole kb and check if any other community member faced such issue already or not; some of those tickets might assist you. If I remember correctly, there are other 503 related issues community faced already; so please feel free to search and check your setup with those tickets. If none of them help, open a new ticket with relevant logs.

I searched but nothing could help me . Here my logs : [oxauth](https://www.dropbox.com/s/1x66qx0a28b62op/oxauth.log?dl=0) [oxtrust](https://www.dropbox.com/s/y9zvo8vqf5h5vai/oxtrust.log?dl=0)