Catia V5R19 did not use DSLS licenses but LUM licenses, so this version of Catia will not point directly to the DSLS server.
You have to install some kind of patch, a "hotfix", in order to point V5R19 at the DSLS server. You can ask your Catia supplier. I think you need one hotfix per version of Catia, so an R19 and an R20.