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

Here is how you can do this:

Open Disney 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).