Kevin Chant has a post covering issues in his experience with the creation of columnstore indexes:
Error due to online statement
It’s a very common error caused usually by somebody copying a rowstore “Create Index” command. The “online=on” option you use with rowstore indexes does not work with creating columnstore indexes yet. For the record the online option will work in SQL Server 2019.
This one I’ve run into, as I like clustered columnstore indexes a lot but occasionally need single-row results from them. If the table is empty, creating an index offline is no problem. But once you get a billion or so rows in it, that’s a non-starter in a 24×7 uptime shop. Read the whole thing.