Someting went really wrong after I've added a new User Group.

From this moment on the child items for my blog page are not loaded anymore. I get this error:

Server error: Contact administrator, see log for full details. Failed to retrieve children for content item

The log says:

Unhandled controller exception occurred for request '{RequestUrl}'","@l":"Error","@x":"System.InvalidOperationException: Missing culture in mapping options.\r\n at Umbraco.Web.Models.Mapping.ContentMapDefinition.GetName(IContent source, MapperContext context) in D:\a\1\s\src\Umbraco.Web\Models\Mapping\ContentMapDefinition.cs:line 207 ...

When I turn off the list view functionality the children are there and everything seems fine.

Interestingly, if I work directely on the remote server I don't run in this problem. So I think it has something to do with permissions. I restarted the app-pool, I restarted the site, I gave write permissions to all folders - nothing works.

This is a big problem for us, since we have 500+ blogposts as child items which can not be handled in treeview - my editors need really the list view.

Any help is highly appreciated! Thank you guys!

Peter