One weird bug: My DeFi Wallet (2.6.5) isn't starting anymore. After

Question

One weird bug: My DeFi Wallet (2.6.5) isn't starting anymore. After

some time it shows:
Unable to start blockchain

Was working fine for weeks and I didn't change anything.

Here is the error from the debug.log:
2021-10-01T08:27:48Z scheduler thread start
2021-10-01T08:27:48Z Binding RPC on address 127.0.0.1 port 8555 failed.
2021-10-01T08:27:48Z Unable to bind any endpoint for RPC server
2021-10-01T08:27:48Z Error: Unable to start HTTP server. See debug log for details.
2021-10-01T08:27:48Z Shutdown: In progress...
2021-10-01T08:27:48Z scheduler thread interrupt
2021-10-01T08:27:48Z Shutdown: done

Any ideas? I downloaded a snapshot already -> same problem