Since the release of iOS 14, the MEATER app needs permission to access your local network to use MEATER Link.
If Local Network Access permissions have been denied, you won't be able to use MEATER Block or MEATER Pro XL in WiFi mode, or connect your single-probe MEATER device to WiFi with a second phone or tablet.
If these permissions are disabled, you can enable them again by going to Settings > MEATER and switching on the "Local Network" toggle.