I have successfully deployed Appian for the first time. Now trying to login usin

A simple way to confirm that this is the issue is to log in using a different browser.
If you were using Chrome, please try IE.

Checked on IE also. Same issue exists. Error: 401

@steven.miccile : I m failing for the first time login only.
Using following credentials on IE version 9.
Username : administrator
password: admin

Also found below error in server.log file. Any clue?

13:18:24,401 INFO [stdout] (http-/0.0.0.0:8080-3) 2016-02-01 13:18:24,400 [http-/0.0.0.0:8080-3] ERROR com.appiancorp.security.csrf.CsrfChannelProcessor -

Attached is a server.log file. Kindly have a look.

server.log

Does the url you are accessing (and that is configured in custom.properties) match the one that is listed in your system hosts file?

In addition to my previous question, have you applied a hotfix on the environment?

Can you please tell me what is mean by System Host file ?
and i have applied a hotfix on the environment.

Able to login finally. Thank you so much Khalil Ben Naceur for all help and support.

Glad to hear that!
For reference purposes, could you please tell us what was the fix in your case?