Portal Address Invalid
If the portal address given to you by “System” shows as invalid when used at a Portal in EUCLID, you will arrive at a different location. The portal address is in this case ‘most’ likely a hidden Star System (Phantom/Shadow Star). It would still exist, but is not accessible through normal means.
You can still get there through Save Editing, or possibly other mods/tools. One such tools is the NMS Service Bot App 
, making it quite easy to get to such systems, even on console. Alternatively you could have someone else go there for you, to join their session.
Once you do arrive in your system, you are advised to create a Base there and make a save, to guarantee you maintain access to it from Teleporter access.