You Asked
What is causing this?
and we said …
ORA-01691: unable to extend lob segment %s.%s by %s in tablespace %s
Cause: Failed to allocate an extent of the required number of blocks for LOB segment in the tablespace indicated.
Action: Use ALTER TABLESPACE ADD DATAFILE statement to add one or more files to the tablespace indicated.
In this case of an ORA-01691 error, the solution is to identify the name of the tablespace associated with the LOB segment and add space to the tablespace using the "alter tablespace *** add datafile yyy size zzz".