Error when connecting the wallet to the umbrel node

Hi, unfortunately I cannot connect either the Ledger Live Wallet or my Sparrow Wallet to my Umbrel Node.

When I select Private Electrum in the Sparrow Wallet and umbrel.local (or the IP) as the server, I always get this error: ErrorMessage{code=-32603, message=unavailable index}

In the Electrs app it also says “Waiting for Bitcoin Node to finish syncing…” Yet the Bitcoin app is 100% synced.

No connection can be established via Bitcoin Core either.

Any ideas what could be causing the error?