its showing 404 error on page auth/login in installation 

mod_rewrite is also enabled on my server  

i am using pap version 7.2

Please, make sure you've followed the installation steps carefully:

https://akaunting.com/docs/installation

I have this issue too,

I unpacked the Akaunting zip to my server, but when I try to access http://akaunting.domain.com (which points to the directory in which i unziped the akaunting 3.1 installation, my server serves me a 404 not found on auth/login.
(note that the server correctly displays an index.php with php info if I place it in that folder instead of akaunting)

Same here - seen this with PHP Cake installs - it is something in the document root or something that eludes me at present. I have installed CentOS 7 some time back, updated it, update PHP to 7.0 (remi repo). I have the following in Apache in its own conf file - akaunting is just a directory off the LAN IP, not a host on its own sitting in its own root doc which is where the issue is for sure - must be .htaccess or something failing.

/etc/httpd/conf.d/lo_akaunting.conf contents:

Alias /akaunting /u/www/akaunting

<Directory /u/www/akaunting>

  Options Indexes FollowSymlinks MultiViews

  AllowOverride All

  Require all granted

  allow from all

</Directory> 

and server LAN IP is 192.168.201.9 so when I go to:

192.168.201.9/akaunting

I get:

192.168.201.9/akaunting/auth/login.php

with the web tab label of "404 Not Found" and page content of:

Not Found

The requested URL /u/www/akaunting/index.php was not found on this server.z

.... but ls -l shows:

-rw-r--r-- 1 apache apache 795 Feb 20  2018 /u/www/akaunting/index.php

Would love to trial the software to see if I can get off the dreaded ancient MYOB software which runs on Windows but is a deal breaker at present as I can't even start the software to run it.

Seeing the same problem with nginx.

Fresh installation

akaunting/index.php => redirects to =>index.php/auth/login => 404

I had this problem too.
I fixed it.
I enabled mod_rewrite in my Apache2 server.

took a few minutes of googling to figure out how.
You'll need to ssh in and have root.