Heroku Push rejected, failed to compile ASP.NET Core app

what is heroku-16?

there are different types of distros(stacks) which contains your app:

• heroku-16
• cedar-14 (supports dotNet-core.)

thats why we will switch to cedar-14

how to fix:

1- install heroku cli. (https://devcenter.heroku.com/articles/heroku-cli)

2- open cmd. type:

cd to/project/Root heroku stack:set cedar-14git push heroku master

You could create a Dockerfile to generate a Docker image runnable on Heroku.

FROM microsoft/aspnetcore-build:2.0 AS build-envWORKDIR /app# Copy csproj and restore as distinct layersCOPY *.csproj ./RUN dotnet restore# Copy everything else and buildCOPY . ./RUN dotnet publish -c Release -o out# Build runtime imageFROM microsoft/aspnetcore:2.0WORKDIR /appCOPY --from=build-env /app/out .CMD ASPNETCORE_URLS=http://*:$PORT dotnet <YOUR_API_NAME>.dll

Then you can publish it to Heroku either directly using these Docker commands:

docker build -t aspnetapp <YOUR_API_NAME>docker login --username=$HEROKU_USERNAME --password=$HEROKU_API_KEY registry.heroku.comdocker tag aspnetapp registry.heroku.com/$HEROKU_APP_NAME/webdocker push registry.heroku.com/$HEROKU_APP_NAME/web

In order these commands:

1. Create a Docker image and builds a release of your project in it
2. Connect to Heroku's docker registry using your credentials
3. Creates a new tag for your image
4. Publishes your image to your Heroku app

However, if your machine does not support Docker, you can also use CircleCI to run these commands. More details here: https://www.codingnagger.com/2018/02/21/continuous-delivery/