I've recently installed alfresco 5.1 on my ubuntu 16.04 server and managed to get it behind my Apache reverse proxy and making it accessible from the Internet.
I'm now trying the android mobile app but - weird - it works well in LAN (where my internal DNS point the FQDN to the apache reverse proxy server), while it's not able to retrieve the repository of a site from an external connection, giving me a:
An Error occurred: org.apache.chemistry.opencmis.commons.exceptions.CmisRuntimeException: Gateway Time-out
I'm able to configure the application from the internet, pointing it to my FQDN, I can browse sites, check my tasks, but whenever I try to fetch files from the main repository or from a site repo, I'll get that error (screenshot in the attachment).
There shouldn't be any difference, both the requests from LAN or WAN are routed to my apache reverse proxy and - by the way - accessing share folder from the outside with any device (https://alfresco.mydomain.com) works great..
Do you have any idea? I haven't find any clue in any log file...