Yes. There are errors on it :
2015/11/23 21:28:06 [error] 31571#0: *18825 connect() failed (111: Connection refused) while connecting to upstream, client: *IP*, server: git.krands.be, request: "GET /g/ HTTP/1.1", upstream: "http://[::1]:6000/", host: "git.krands.be", referrer: "https://krands.be/yunohost/sso/"
2015/11/24 21:48:52 [error] 31573#0: *28500 connect() failed (111: Connection refused) while connecting to upstream, client: *IP*, server: git.krands.be, request: "GET /g/ HTTP/1.1", upstream: "http://[::1]:6000/", host: "git.krands.be", referrer: "https://krands.be/yunohost/sso/"
2015/11/24 21:48:56 [error] 31573#0: *28500 connect() failed (111: Connection refused) while connecting to upstream, client: *IP*, server: git.krands.be, request: "GET /g/admin HTTP/1.1", upstream: "http://[::1]:6000/admin", host: "git.krands.be"
2015/11/24 21:49:01 [error] 31573#0: *28500 connect() failed (111: Connection refused) while connecting to upstream, client: *IP*, server: git.krands.be, request: "GET /g/?admin HTTP/1.1", upstream: "http://[::1]:6000/?admin", host: "git.krands.be"
2015/11/25 21:20:55 [error] 31573#0: *32596 connect() failed (111: Connection refused) while connecting to upstream, client: *IP*, server: git.krands.be, request: "GET /g/ HTTP/1.1", upstream: "http://[::1]:6000/", host: "git.krands.be", referrer: "https://krands.be/yunohost/sso/"
2015/11/25 21:25:27 [error] 31573#0: *32649 connect() failed (111: Connection refused) while connecting to upstream, client: 2a02:a03f:c76:d800:f606:69ff:fe0c:1d4a, server: git.krands.be, request: "GET /g/ HTTP/1.1", upstream: "http://[::1]:6000/", host: "git.krands.be", referrer: "https://krands.be/yunohost/sso/"
2015/11/26 08:48:01 [error] 31572#0: *34046 connect() failed (111: Connection refused) while connecting to upstream, client: 193.190.77.225, server: git.krands.be, request: "GET /g/ HTTP/1.1", upstream: "http://[::1]:6000/", host: "git.krands.be", referrer: "https://krands.be/yunohost/sso/"
So there are things to reload or delete, which makes it difficult for it to load ?
I see nothing wrong with your logs, i got pretty much the same (even the ldap error) but gogs works fine on my server.
It did, before I reboot the machine 
EDIT : I installed Gogs once, after the reboot, I couldn’t access to it. When I saw that, I reinstalled Gogs to make sure there where new files in it.
When you uninstall an app, are there remaining files ? It’s like something need to be deleted somewhere and/or refresh it.