Insert using CTE (WITH instruction in select) raises ORA-00942

LS,

Oracle DB versie 19.3 on Linux platforms

I'm trying to run a simple INSERT statement based on a CTE (WITH instruction in select); a CTE is used to 'compute' rows to be inserted in a TABLE. That TABLE is actually a public synonym pointing to a view pointing to the actual table the rows will need to be added to.

When I run the insert connected as the table/view schema 'owner', everything works fine.

When I grant access/insert privs to/on the view to a third user, and then execute the insert as thta third user, I always get ORA-00942; whatever happens. Access/inserts are possible without any problem if not using CTE (WITH instruction), using PLSQL, ...