Gitlab stopped working after recent update


I’ve installed gitlab on my debian server (8.2) and I recently made an update (apt-get update, apt-get upgrade). After that it still seemed to work. Today I made a restart and I cannot access the gitlab webpage from remote anymore. Also my owncloud server does not work anymore if that helps for solving the gitlab problem. My configuration on my network is as follows:

gitlab runs on port 22 -> forwarded to 10001 (accessing usualy with “ip:10001”, doesnt work anymore)
ssh is forwarded to port 10000 (still WORKS!)
owncloud is forwarded to port 10002 (doesnt work anymore)

To be honest I have no clear understanding which config files are important in gitlab for this access problem, since the last time it was more like try and error with the few config files (I think it was 2 or 3 config files to edit) since I couldnt solve it using the installation info.

Can someone help me with this issue?