@SuperHammy3 that is not a helpful suggestion
@ThEDaRkNeSSLoRD the reason for this issue is likely to be:
- broken/conflicting dimension type ID configs, either in Galacticraft itself or a Galacticraft add-on mod like ExtraPlanets
- if you're playing on a multiplayer server, different dimension ID configs on client and server
Fix or delete your Galacticraft and add-on configs (on client and server) and everything should be OK.
If you still can't make it work, try without Galacticraft add-ons. Usually people have problems trying to combine 2 or more different Galacticraft add-ons.