Archived Support Site

This support site is archived. You can view the old support discussions but you cannot post new discussions.

ASP.NET Core 502 - Web server received an invalid response while acting as a gateway or proxy server.

mh453's Avatar


11 Jan, 2018 04:07 PM

Hi I have deployed a ASP.NET Core project to the free tier of AppHarbor however its takes quite a while to load. When I run this app locally on my machines it work fine and is very quick to load.

Sometime it takes so long to load on AppHarbor it times out I get a 502 - Web server received an invalid response while acting as a gateway or proxy server. How are application managed when you deploy them to appharbor ?

Here is the URL -

  1. Support Staff 1 Posted by rune on 13 Jan, 2018 05:40 AM

    rune's Avatar

    Hi Bob,

    Since the issue appears to occur at startup you may want to minimize the time it takes to warm up. You likely don't experience this issue when you redeploy your application as AppHarbor will warm up the new worker before routing data to it (for up to at least 2 minutes on the free plan). However, applications on the Canoe plan will time out after 20 minutes of inactivity, so if your app isn't accessed for a while it'll cause the app to respond slower when it's restarted.

    You can likely avoid this by upgrading to the Catamaran plan. Workers on that (and the Yacht) plan will only idle out after 36 hours of inactivity. Apps on the paid plans also have 5 minutes to warm up before AppHarbor starts routing traffic to it, and you get an extra worker unit you can use to scale the app vertically (and get twice as much CPU resources which is often the bottleneck during startup).

    I hope this helps, but please don't hesitate to reach out if there's anything else I can help with!


  2. rune closed this discussion on 13 Jan, 2018 05:40 AM.

Discussions are closed to public comments.
If you need help with AppHarbor please start a new discussion.

Keyboard shortcuts


? Show this help
ESC Blurs the current field

Comment Form

r Focus the comment reply box
^ + ↩ Submit the comment

You can use Command ⌘ instead of Control ^ on Mac