It could be due to one of the following reasons,
1. One user is trying to modify the underlying Data Source Configurations while the other user is trying to create the Base View.
1. Any of the underlying elements were locked by another session for updating the metadata.
1. Multiple users are trying to create the same view simultaneously.
1. In case VCS is enabled, some of the underlying elements are not in sync with the VCS repository server, especially Data Source Configurations.
1. In case Cache Status is On, either the Cache Database connection is not working or some of the underlying objects are locked in Cache Database.
I would suggest you to restart the VDP Server and then try creating the Base View.
Hope this helps.