Hi,

Regarding above issue:

• First of all make sure your Odoo 13CE must have latest Odoo pull. If not then kindly update the Odoo 13 latest pull because in previous commit that was the issue.

• Secondly, sometime in other window same Odoo is open with expired session.

• Third, kindly enable Odoo developer mode with assets then check the issue by right clicking on the browser and inspect element.

• • After that inside the console tab you will be able to check the exact error.

  • Kindly check that error and if you are not able to fix that error then share with me. So I can look on to that problem.

Feel free to ask in case you have any doubt related to the above point.

Thanks,

Ashish Singh (Team Lead)

Webkul Software Private Limited.

1. Navigating in to the correct folder

The first thing that you will need to do is to navigate in to the correct folder from your terminal. Usually your Odoo is installed right under the root folder and has a structure along the lines of /odoo/odoo-server. In my local example I’ve installed an Odoo 9 under /odoo9/odoo9-server:

So, how do you know in which folder you need to be? if you see the same structure as in my above screenshot you’re in the right place. You should see the odoo.py and addons folder.

2. Fetch content from Github

Now that you’re in the correct folder you should fetch the content from Github in order to apply it locally later on. Fetch the content from Github:

1

So, what does this line do? Sudo will execute this command with administrator priveleges, git fetch will tell the system that we want to fetch content from github, origin refers to the origin where Odoo comes from (http://github.com/odoo/odoo) and 9.0 is the Odoo version.
Tip: If you have Odoo version 8 you should replace 9.0 with 8.0.
After running this command you will see the following result:

3. Apply all changes

You now have everything fetched and you should now tell the system to apply this. At this point the system knows which files and changes need to be made, but you didn’t make them yet. You can do this with git reset. The code:

sudo git reset --hard origin/9.0

Tip: git reset –hard will apply all changes, no matter what. If you did add custom code in already existing modules (so in the source code and not in a self made module) you should not use this. Your custom code will be overwritten with this! This is however against all the rules, so if you do code in the source code please start with creating your own modules in place of adding in the source code.
Tip #2: Do you have another version? Simply change 9.0 with the Odoo version you have running. For example if you have Odoo 8:

sudo git reset --hard origin/8.0

After you’ve used this command you will see a result similar to this:

So, what does this refer to? If I open up Github and look at the latest change that has been made to Odoo you will see that these match up:

As you can see your Odoo code is now up-to-date and is at the latest change that has been made by Odoo.

4. Updating the database

Congratulations, you’ve already updated your whole Odoo code! That was simple, right? There is just one more thing to do. You should now update your database so that the database knows about all changes and applies them in the database.
There are multiple ways to do this but the most simple one is to restart the Odoo service with the correct parameters to update the odoo. Every Odoo has a service running and usually has a name along the lines of odoo-server. Type the following command in your terminal:

sudo service odoo9-server restart -u all -d YourDatabaseName

I already had workers configured.
I followed the reply of @Ashish Singh, but my problem persisted. 
I have the odoo and postgres in distinct VM, the only thing that solved my problem was when I open the port 5432 in my odoo VM... I don't understand why but it worked. 

firewall-cmd --zone=public --add-port=8069/tcp --permanent
firewall-cmd --zone=public --add-port=8072/tcp --permanent
firewall-cmd --zone=public --add-port=5432/tcp --permanent
firewall-cmd --reload

Hope this help someone.