The error message indicates that the permission resourcemanager.projects.list is not valid for use in a custom role. This is because certain permissions are restricted and cannot be included in custom roles. The correct action is to remove the invalid permission from the role configuration before attempting to create the custom role again. Option A suggests adding a different permission, which does not resolve the issue of the invalid permission. Option B suggests trying a different role name, which does not address the permission issue. Option D suggests adding another permission, which also does not resolve the invalid permission problem. Therefore, the correct answer is to remove the invalid permission as stated in option C.