Why do I get an "Unable to write to the configuration file" error when I try to use the webapps-config script to configure MATLAB Web App Server?

I'm trying to use the webapps-config and/or webapps-setup scripts to make changes to my MATLAB Web App Server configuration, but I get the following error when I run them:

Unable to write to the configuration file

I am already using a terminal with administrative privileges, but the issue persists.

Answer 1

[MathWorks Support Team]

The "Unable to write to the configuration file" error usually indicates that the current user (i.e. the user account that is executing the given terminal commands) does not have sufficient permissions to write to the MATLAB Web App Server configuration file. 

To resolve this issue, navigate to your installation's config folder and ensure that the current user has "write" permissions for the webapps.config file. The folder location varies based on your operating system:

https://www.mathworks.com/help/webappserver/ug/service-info-and-folder-locations.html

There are a number of situations that may cause this issue to occur: 

• If you register the server and apps services to use the same user account, this error may appear during setup or later configurations.
• If you register the apps service to use the same user account as is running the setup process, setup may fail with this error. 
• If you set up your server with existing user accounts and the groups/accounts are altered or removed following setup, you may encounter this error.

For these reasons, it is highly recommended that you register the server and apps services with separate dedicated non-administrator accounts.