Getting started with .net core

I tried for quite some time to get EventStoreDb running, but always run into issues. I have found the getting started in the repo and it has a docker compose file which loads EventStoreDb nicely. But it has no connection string. If I use the connection string from the reading events example I always get the following error (.net 5, mac):

Unhandled exception. System.InvalidOperationException: Status(StatusCode="Internal", Detail="Error starting gRPC call. HttpRequestException: The SSL connection could not be established, see inner exception. IOException: Cannot determine the frame size or a corrupted frame was received.", DebugException="System.Net.Http.HttpRequestException: The SSL connection could not be established, see inner exception.
     ---> System.IO.IOException: Cannot determine the frame size or a corrupted frame was received.
       at System.Net.Security.SslStream.ReceiveBlobAsync[TIOAdapter](TIOAdapter adapter)
       at System.Net.Security.SslStream.ForceAuthenticationAsync[TIOAdapter](TIOAdapter adapter, Boolean receiveFirst, Byte[] reAuthenticationData, Boolean isApm)
       at System.Net.Http.ConnectHelper.EstablishSslConnectionAsyncCore(Boolean async, Stream stream, SslClientAuthenticationOptions sslOptions, CancellationToken cancellationToken)
       --- End of inner exception stack trace ---
       at System.Net.Http.ConnectHelper.EstablishSslConnectionAsyncCore(Boolean async, Stream stream, SslClientAuthenticationOptions sslOptions, CancellationToken cancellationToken)
       at System.Net.Http.HttpConnectionPool.ConnectAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)
       at System.Net.Http.HttpConnectionPool.GetHttp2ConnectionAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)
       at System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage request, Boolean async, Boolean doRequestAuth, CancellationToken cancellationToken)
       at System.Net.Http.RedirectHandler.SendAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)
       at System.Net.Http.HttpClient.SendAsyncCore(HttpRequestMessage request, HttpCompletionOption completionOption, Boolean async, Boolean emitTelemetryStartStop, CancellationToken cancellationToken)
       at Grpc.Net.Client.Internal.GrpcCall`2.GetResponseHeadersCoreAsync()")
     ---> Grpc.Core.RpcException: Status(StatusCode="Internal", Detail="Error starting gRPC call. HttpRequestException: The SSL connection could not be established, see inner exception. IOException: Cannot determine the frame size or a corrupted frame was received.", DebugException="System.Net.Http.HttpRequestException: The SSL connection could not be established, see inner exception.
     ---> System.IO.IOException: Cannot determine the frame size or a corrupted frame was received.
       at System.Net.Security.SslStream.ReceiveBlobAsync[TIOAdapter](TIOAdapter adapter)
       at System.Net.Security.SslStream.ForceAuthenticationAsync[TIOAdapter](TIOAdapter adapter, Boolean receiveFirst, Byte[] reAuthenticationData, Boolean isApm)
       at System.Net.Http.ConnectHelper.EstablishSslConnectionAsyncCore(Boolean async, Stream stream, SslClientAuthenticationOptions sslOptions, CancellationToken cancellationToken)
       --- End of inner exception stack trace ---
       at System.Net.Http.ConnectHelper.EstablishSslConnectionAsyncCore(Boolean async, Stream stream, SslClientAuthenticationOptions sslOptions, CancellationToken cancellationToken)
       at System.Net.Http.HttpConnectionPool.ConnectAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)
       at System.Net.Http.HttpConnectionPool.GetHttp2ConnectionAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)
       at System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage request, Boolean async, Boolean doRequestAuth, CancellationToken cancellationToken)
       at System.Net.Http.RedirectHandler.SendAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)
       at System.Net.Http.HttpClient.SendAsyncCore(HttpRequestMessage request, HttpCompletionOption completionOption, Boolean async, Boolean emitTelemetryStartStop, CancellationToken cancellationToken)
       at Grpc.Net.Client.Internal.GrpcCall`2.GetResponseHeadersCoreAsync()")
       --- End of inner exception stack trace ---
       at EventStore.Client.Interceptors.TypedExceptionInterceptor.<AsyncClientStreamingCall>b__5_0[TRequest,TResponse](Task`1 t) in /Users/andi/repos/EventStore-Client-Dotnet/src/EventStore.Client/Interceptors/TypedExceptionInterceptor.cs:line 54
       at System.Threading.Tasks.ContinuationResultTaskFromResultTask`2.InnerInvoke()
       at System.Threading.Tasks.Task.<>c.<.cctor>b__277_0(Object obj)
       at System.Threading.ExecutionContext.RunFromThreadPoolDispatchLoop(Thread threadPoolThread, ExecutionContext executionContext, ContextCallback callback, Object state)
    --- End of stack trace from previous location ---
       at System.Threading.ExecutionContext.RunFromThreadPoolDispatchLoop(Thread threadPoolThread, ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.Tasks.Task.ExecuteWithThreadLocal(Task& currentTaskSlot, Thread threadPoolThread)
    --- End of stack trace from previous location ---
       at EventStore.Client.EventStoreClient.AppendToStreamInternal(AppendReq header, IEnumerable`1 eventData, EventStoreClientOperationOptions operationOptions, UserCredentials userCredentials, CancellationToken cancellationToken) in /Users/andi/repos/EventStore-Client-Dotnet/src/EventStore.Client.Streams/EventStoreClient.Append.cs:line 125
       at reading_events.Program.Main(String[] args) in /Users/andi/repos/EventStore-Client-Dotnet/samples/reading-events/Program.cs:line 22
       at reading_events.Program.<Main>(String[] args)