It says in the Manuel for the Presonus Studiolive 64S
Static Self (Self-Assigned). The IP address is assigned automatically, but stays
the same thereafter until you need to change it. In this mode, an Apply button is shown. Touch this button to auto-assign a new static IP address to your StudioLive.
It does not say how to change from Self Assn mode back to Dynamic as my computer is now only reading the Ethernet connection as Self Assn and will not allow me to access the 64S mixer.
I have tried find how to restore to factory settings but cannot find the software/firmware on the Persons site.