problem with running the solution

[hdsali]

Hello every body,

I got the solution code and tried to run it.
but I receive following error:

info: Microsoft.AspNetCore.SpaProxy.SpaProxyMiddleware[0]
SPA proxy is not ready. Returning temporary landing page.
fail: Microsoft.AspNetCore.SpaProxy.SpaProxyLaunchManager[0]
Couldn't start the SPA development server with command 'npm start'.

any body can help me to resolve this issue?
Thank you in advance