Can connect to Salesforce connected app locally but not when published in Azure function

Question

I'm having this issue with my custom integration to Salesforce from an Azure function right now. For some reason when I test locally and use the local endpoint with Postman I can authenticate with Salesforce just fine but when I publish my Azure function to the cloud and I swap out the endpoint my authentication fails for Salesforce. The exact error message being authentication failure.

At first I thought there must be something wrong with my IP settings for the connected app in Salesforce but I've tested setting Relax IP Settings as well as not defining a Trusted IP Range for OAuth Web server flow and still no success. Here are a couple of screenshots of my settings.

Any ideas why I can authenticate locally but not once I publish to my cloud service in Azure? (I'm using SalesForceSharp to authenticate if that makes any difference)

Answer 1

Finally figured out what the disconnect between my cloud environment (Azure) and Salesforce was when I dug into my login history in Salesforce and found attempts to login from an insecure location.

Apparently different SSL/TLS defaults are setup for local versus cloud environments.

https://github.com/Azure/Azure-Functions/issues/482

Once I input this line at the top of my function and published everything got back to working again.

System.Net.ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;