My customer running on ExaCC (Exadata Cloud@Customer) was getting “ORA-64307: Exadata Hybrid Columnar Compression is not supported for tablespaces on this storage type” on one of his test databases.
I did test connecting to SYS and no problem. Then I try to do using his tablespace and indeed, I get the error:

Quite going around, to check what was different on the user tablespace than on others. I test a self created tablespace and it works.
Strange. Until I found that… some datafiles were not in ASM!

Seems the ASM Diskgroup is almost full and the client DBA just put the datafiles somewhere else!