The issue can be fixed by re-enabling the cross play settings.

Here is how you can do this:

Open Dreamlight Valley: Start the game and go to the main menu.

Access Settings: Look for the gear icon or “Settings” in the main menu and select it.

Cross-Play Setting: In the settings, go to the “Gameplay” or “Online” tab, depending on the menu layout. Look for the “Cross-Play” or “Cross-Platform Play” setting.

Enable Cross-Play: Toggle this setting to “On” or “Enabled.” This will allow cross-play to be active again.
Save and Restart (if necessary).