Salesforce's Spring '20 release enforced a critical update that required customization of the application permissions for direct read access to custom settings. If the application permissions were not adjusted accordingly before the enforcement date, the user may receive the error after selecting the Create Billing button on the Billing Preview.

Why do I get the error below when I try to create a billing from an account?

Your organization's billing related picklist values have been modified and may result in an unpredictable outcome when creating new billings. Please ensure your organization uses the predefined picklist values for Disposition and Status.

To minimize the impact on your users, admins with the Customize Application permission can grant read access to specific or all custom settings.

To grant a specific profile or permission set read access to custom settings:

1. Go to the profile or permission set you want to grant access to.
2. Click the Custom Setting Definitions permission.
3. Click Edit, add the custom setting to the Enabled Custom Setting Definitions list, and then click Save.

To grant profiles or permission sets read access to all custom settings:

1. Search for Profiles or Permission Sets from Setup, then click the name of the profile or permission set and click Edit.
2. In the Administrative Permissions section, check View All Custom Settings.
3. Click Save.

With the Restrict access to custom settings permission enabled, permissions are enforced as follows:

• Customize Application permission - Read and write access to all custom settings.
• Custom Setting Definitions - Read access to specific custom settings outside the system context. Users must be granted access through profiles and permission sets.
• View All Custom Settings permission - Read access to all custom settings outside of the system context.
• View Setup and Configuration permission - Read access to custom settings in Setup. Users must be granted access to specific custom settings through profiles and permission sets, or be granted the View All Custom Settings permission.