Hi Dhivya,

In Odoo, if you add new fields in res_users, res_partner etc, you need to upgrade the module as soon as you restart the service. So you have can either restart the service from command line and also pass the your custom module as an argument to update it at the same time. In order to do this stop your odoo service and run the following command.

./odoo-bin -c /path/config_file_name -d database_name -u module_name

This will upgrade your module and you won't get the internal server error. Another way is to open the the custom module from the Apps menu. You can see the upgrade and uninstall button now. Now restart the service and when the service restart, upgrade the module and it will upgrade without any issues.