What could be the problem with redirecting a request through nginx?

Question

Nginx

The question is of course quite specific and rather abstract, but atlassian's Hindu support refuses to look for a problem, citing the fact that the problem is in nginx and it's none of their business.
Essence:
There are 2 virtual machines, one with

1. Ubuntu Server 14.04 + Oracle Java 1.8.0_25 + nginx 1.4.6 + postgresql 9.3.5
2. Linux Mint 17.1 + Oracle Java 1.8.0_25 + nginx 1.4.6 + postgresql 9.3.5

and in both the ill-fated Atlassian Crowd.
When configuring (SAME) and starting a redirect from an external address goes to the tomcat server, the service is installed, but then when you try to log in to the ubuntu server, it throws an error , but if you do all the same actions on linux mint, then everything will install perfectly and work without a single errors. If you install crowd on the ubuntu server without nginx redirect, using IP:PORT as an access string, then everything works without problems. Those. the problem occurs when proxying through nginx to ubuntu .. But the versions are the same .... Tell me which way to dig? (

Answer 1

The problem must be corrected in nginx, instead of names, go through the IP address

Answer 2

But that didn't help?
In the /crowd.properties file, change the password line to "To7CfmPz";
And use following command in DB:
UPDATE cwd_application
SET credential = '{PKCS5S2}+ebYspXujIGikRoLVenN/BpbtwEg+WfR1u1Okk1BJpFG4nJwbeAr0Sv5U+YG7x5k'
WHERE application_name = 'crowd';
Restart Crowd

Answer 3

Considering that no Mint exists, and this is Ubuntu with a repository with a couple of its own DEs, the problem is not in the distribution. See where the differences are in the configs.