Front end fails if 3000 port is not available

If other process uses 3000 port then app starts on the next available port but front end still sends requests to 3000:

Reproduce the app with port 3000 occupied and observe the port selected at startup and the port used by front-end requests. Trace the startup and request configuration to identify where the selected port is communicated; done means the front end uses the available port and requests succeed when 3000 is unavailable.

Written by the indexing model from the issue text.