I encountered an issue

Hello
(I use Macbook)
I just opened a wallet on 'Specter'. I sent bitcoin to this wallet, but the BTC still didn't show up in my wallet after a long time.
After I quit the App and open it again, it shows the below:
'Bitcoin Core files missing. Make sure Bitcoin Core is installed within Specter'\
'Wallets are unavailable if Specter is not connected to Bitcoin Core!'

I cannot log into my wallet. What should I do now? I need to access my wallet as soon as possible.