Hi Nehal,

I encountered that issue also in my system. It turned out that it was not related to odoo itself but to NGNIX settings for request file size.

Original post:

http://craftcms.stackexchange.com/questions/2328/413-request-entity-too-large-error-with-uploading-a-file

413 errors occur when the request body is larger than the server is configured to allow. Here’s how you can fix it, depending on your web server:

Apache: Set the LimitRequestBody directive in either your httpd.conf file or a local .htaccess file. (http://stackoverflow.com/a/3719358/1688568)

Nginx: Set the client_max_body_size directive in nginx.conf (http://www.cyberciti.biz/faq/linux-unix-bsd-nginx-413-request-entity-too-large/)

IIS: Set the uploadreadaheadsize config setting (http://blogs.msdn.com/b/jiruss/archive/2007/04/13/http-413-request-entity-too-large-can-t-upload-large-files-using-iis6.aspx)

You also might want to try increasing PHP’s upload_max_filesize and post_max_size settings in php.ini or using the php_value directive in your .htaccess file if you’re using Apache (http://davidwalsh.name/php-values-htaccess).

That helped to solve it on my side. The issue was also that on webiste You will not see the message from HTTP server. You can see it when You try to add files in Settings -> Technical -> Database Structure -> Attachments.

I hope that that will help others too:)