Nothing was written to either oxauth.logs of both servers.
So I removed the U/P Login handler from the second gluu server to which asimba is redirecting to.
Now I get forwarded to the "normal" gluu login page and the login is working. Thank you for this!
After the successful login I got forwarded to the first gluu server (the proxy one). The page says "Failed to authenticate" and is located at <gluu-1>/oxauth/error.htm?cid=106.
oxauth.log says:
```
2016-09-18 18:23:10,904 ERROR [org.xdi.oxauth.service.external.ExternalAuthenticationService]
Traceback (most recent call last):
File "<iostream>", line 268, in authenticate
AttributeError: 'NoneType' object has no attribute 'entrySet'
at org.python.core.Py.AttributeError(Py.java:205)
...
```
oxauth_script.logs says:
```
2016-09-18 18:23:00,462 INFO [org.xdi.service.PythonService] (ajp-bio-127.0.0.1-8009-exec-38) Saml. Prepare for step 1
2016-09-18 18:23:00,468 INFO [org.xdi.service.PythonService] (ajp-bio-127.0.0.1-8009-exec-38) Saml. Prepare for step 1. Prepared assertionConsumerServiceUrl: 'https://<gluu-1>/oxauth/postlogin'
2016-09-18 18:23:00,502 INFO [org.xdi.service.PythonService] (ajp-bio-127.0.0.1-8009-exec-38) Saml. Prepare for step 1. external_auth_request_uri: 'https://<gluu-1>/asimba/profiles/saml2/sso/web ?SAMLRequest=...'
2016-09-18 18:23:10,880 INFO [org.xdi.service.PythonService] (ajp-bio-127.0.0.1-8009-exec-38) Saml. Authenticate for step 1
2016-09-18 18:23:10,884 INFO [org.xdi.service.PythonService] (ajp-bio-127.0.0.1-8009-exec-38) Saml. Authenticate for step 1. saml_response: '...'
2016-09-18 18:23:10,895 INFO [org.xdi.service.PythonService] (ajp-bio-127.0.0.1-8009-exec-38) Saml. Authenticate for step 1. saml_response_name_id: '_2f22f2d8ffa01d566b2c15d02edbc3a7!https://<gluu-1>/saml'
2016-09-18 18:23:10,898 INFO [org.xdi.service.PythonService] (ajp-bio-127.0.0.1-8009-exec-38) Saml. Authenticate for step 1. attributes: '{country: [Netherlands]}'
2016-09-18 18:23:10,899 INFO [org.xdi.service.PythonService] (ajp-bio-127.0.0.1-8009-exec-38) Saml. Authenticate for step 1. Attempting to find user by oxExternalUid: saml: '_2f22f2d8ffa01d566b2c15d02edbc3a7!https://<gluu-1>/saml'
2016-09-18 18:23:10,903 INFO [org.xdi.service.PythonService] (ajp-bio-127.0.0.1-8009-exec-38) Saml. Authenticate for step 1. There is no user in LDAP. Adding user to local LDAP
2016-09-18 18:23:10,904 INFO [org.xdi.service.PythonService] (ajp-bio-127.0.0.1-8009-exec-38) Saml. Authenticate for step 1. Using next attributes mapping 'None'
```
Funny though there's the country=Netherlands again.
Thanks for all your time helping me :)