Troubleshooting

Fixes for common FlowReactor problems, including ports in use, database SSL and MySQL login errors, unreachable services from Docker, HTTPS metadata errors and activation issues.

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A service won't start

could not listen on 127.0.0.1:… means another program is using the port. It's often a previous copy of the real service, such as a DynamoDB Local on 8000. Either stop that program, or stop the service in FlowReactor, change its Port under Configuration › Addresses, and start it again.

My application can't reach FlowReactor

  • Check the service is Running, and that your application uses 127.0.0.1 and the port shown in the service header.
  • From Docker or a virtual machine: services listen on 127.0.0.1 only, so they can't be reached from containers, virtual machines or other computers. Run your application on the same computer as FlowReactor.

Database connections fail

PostgreSQL with SSL. FlowReactor doesn't support TLS yet. Use sslmode=disable or prefer (SSL Mode=Disable in Npgsql). With require or stricter, the client refuses to connect. Databases that only accept TLS can't be proxied yet.

MySQL with TLS required. The timeline says the client requires TLS. Use SslMode=Preferred or SslMode=None.

MySQL 8 login fails. Without TLS, caching_sha2_password may need the server's public key: add AllowPublicKeyRetrieval=true (or your driver's equivalent), or connect once directly to the database so it caches the login.

Could not reach upstream. FlowReactor can't reach the real database. Check Real database host and its port under Configuration › Addresses, and that the database is running.

Login refused by the server. The database rejected the username or password. FlowReactor passes credentials through unchanged, so use the same ones as when you connect directly.

Token validation fails against Cognito

  • "The MetadataAddress or Authority must use HTTPS" (ASP.NET Core): the simulator speaks plain HTTP. Set RequireHttpsMetadata = false in development.
  • Audience errors: access tokens carry client_id, not aud. Don't validate the audience of access tokens, or check client_id yourself.
  • Issuer mismatch: the issuer is http://127.0.0.1:9229/<pool id>. Copy it from User pools › Connect your app. If you changed the pool id, update your configuration.

An AWS SDK call fails with UnknownOperationException

The call isn't supported by the simulator yet, and the message names it. See what's supported for DynamoDB and Cognito.

My application is stuck

Check the header for a paused count: a breakpoint or Pause traffic may be holding a request. Continue it from Paused now, choose Resume traffic, or turn the breakpoint off. Also check for Latency under Faults.

Activation and the license

  • The browser didn't open: use the copy-link button under the code.
  • The code expired: choose Try again.
  • Locked after being offline: connect to the internet; FlowReactor unlocks within a few minutes, or choose Check now.

More in Trial, licenses and updates.

Getting help

  1. In Settings › Logs & diagnostics, set Log level to Debug and reproduce the problem.
  2. Choose Copy diagnostics. It includes your version, system, license status and settings, but no keys, tokens or project data.
  3. Contact support with the diagnostics, the Installation ID from Settings › License, and the log file from Open folder if you can.