In certain cases, when you try to assign the catalog admin role to a user, the "Oops, something went wrong." error might be displayed. This usually happens on catalogs that are subsites. By design, a subsite inherits the permissions settings of the root or top-level site but when you assign unique permissions to a subsite, it no longer inherits permissions from their parent site. So, checking your catalog for conflicts caused by the permissions issues inherited from the parent site can help to find a solution to the issue.
This article provides information about how to check and resolve permissions issues when adding catalog admins to a catalog that is a SharePoint subsite.
Required role: SharePoint site owner or SharePoint admin.
To check and manage the permissions at a site level, follow these steps:
1. On the course catalog site page, go to Settings > Site permissions.
2. On the opened Permissions panel, select Advanced permissions settings.
3. On the opened page that shows the site permissions, you'll see the "Some content on this site has different permissions from what you see here" and a link called Show these items. Select the Show these items link.
You'll see a list of exceptions with unique permissions configured for them.
4. Next to the item for which you want to configure permissions, select the relevant action: manage permissions or view exceptions.
Selecting view exceptions redirects you to the page where the manage permissions option is available for the item in question.
5. On the opened page, you can restore permission inheritance from a parent site using the Delete unique permissions option. When you select this option, all changes that you've made to permissions for this item will be removed, and the inherited permissions and security settings from the parent site will be restored.
Find more information about the SharePoint permissions inheritance in this article.