I've been trying to get started with WebJobs, so I've started with a template .Net Framework WebJob project. The only modifications I've made are setting the relevant variables in the app.config, and outputting the message it's receiving from a queue as a console message.
When I upload it to an app service, I get the error
Unhandled Exception: System.IO.FileNotFoundException: Could not load file or assembly 'Microsoft.Azure.WebJobs.Host, Version=1.1.2.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The system cannot find the file specified.
This makes sense, because I've given it the exe, but that doesn't include all the dependencies. I figured it would download them from nuget, but what about custom package sources? How would it get those? There must be something I'm missing but I have no idea what.
I understand you're trying to deploy a web job to an existing App service. There are two options.
Consider what you already did, Option 1: You can zip the exe with all dependencies and upload the .zip file from the release folder. You have build the project in release mode.
Option 2, you can publish from within MS Visual Studio by right-click on your project and Publish, then Add a publish profile-> Azure-> Azure Webjob->Choose an existing App service. You will need to log in to an account with an Azure subscription.
I recommend visiting MS learn website to understand how it works.
https://learn.microsoft.com/en-us/azure/app-service/webjobs-create