Try to debug a local function app

Oct 13, 2025 by wbrum.org 147 views

Environment Variable AZURE_AUTHORITY_HOST Causes Error: "Exception has been thrown by the target of an invocation."

When working with Azure Functions, developers often encounter various issues that can hinder their productivity. One such issue is related to the environment variable AZURE_AUTHORITY_HOST. In this article, we will delve into the problem of AZURE_AUTHORITY_HOST causing an error when using the func command line tool, specifically the error message "Exception has been thrown by the target of an invocation."

The error "Exception has been thrown by the target of an invocation" is a generic error message that does not provide much information about the root cause of the issue. However, in this case, the presence of the environment variable AZURE_AUTHORITY_HOST is the culprit. This variable is used to specify the authority host for Azure Active Directory (AAD) authentication.

The issue is observed in version 4.0.6821 of the Azure Functions runtime. When the environment variable AZURE_AUTHORITY_HOST is present, the func command line tool throws an error. This includes scenarios where the variable is loaded using tools like dotenv, making it challenging to troubleshoot the issue.

To reproduce the issue, follow these steps:

Set an environment variable with the name AZURE_AUTHORITY_HOST: You can set this variable using the set command in Windows or the export command in Linux/Mac. For example, you can set the variable to a value like https://login.microsoftonline.com.
Try to debug a local function app: Once the environment variable is set, try to debug a local function app using the func command line tool. You will encounter the error "Exception has been thrown by the target of an invocation."

To troubleshoot the issue, you can try the following:

Check the environment variable: Verify that the environment variable AZURE_AUTHORITY_HOST is set and its value is correct.
Remove the environment variable: Try removing the environment variable AZURE_AUTHORITY_HOST and see if the issue persists.
Use a different authentication method: If you are using AAD authentication, try using a different authentication method, such as Azure Active Directory (AAD) B2C or Azure Active Directory (AAD) v2.
Check the Azure Functions runtime logs: Check the Azure Functions runtime logs for any errors or warnings related to the AZURE_AUTHORITY_HOST environment variable.

If you cannot remove the environment variable AZURE_AUTHORITY_HOST, you can try the following workarounds:

Use a different environment variable: Instead of using AZURE_AUTHORITY_HOST, try using a different environment variable, such as AZURE_TENANT_ID or AZURE_CLIENT_ID.
Use a configuration file: Instead of using environment variables, try using a configuration file, such as local.settings.json, to store your Azure Functions configuration.
Use a different authentication method: If you are using AAD authentication, try using a different authentication method, such as Azure Active Directory (AAD) B2C or Azure Active Directory (AAD) v2.

In conclusion, the presence of the environment variable AZURE_AUTHORITY_HOST can cause an error when using the func command line tool, specifically the error message "Exception has been thrown by the target of an invocation." To troubleshoot the issue, you can try removing the environment variable, using a different authentication method, or checking the Azure Functions runtime logs. If you cannot remove the environment variable, you can try using a different environment variable, a configuration file, or a different authentication method.
Q&A: Environment Variable AZURE_AUTHORITY_HOST Causes Error

In our previous article, we discussed the issue of the environment variable AZURE_AUTHORITY_HOST causing an error when using the func command line tool, specifically the error message "Exception has been thrown by the target of an invocation." In this article, we will provide a Q&A section to help you better understand the issue and its solutions.

A: The environment variable AZURE_AUTHORITY_HOST is used to specify the authority host for Azure Active Directory (AAD) authentication. It is typically used in Azure Functions to authenticate with Azure Active Directory.

A: The environment variable AZURE_AUTHORITY_HOST is causing an error because it is not a required environment variable for Azure Functions. When it is present, it can cause conflicts with the Azure Functions runtime, leading to the error "Exception has been thrown by the target of an invocation."

A: To troubleshoot the issue, you can try the following:

Check the environment variable AZURE_AUTHORITY_HOST to ensure it is not set.
Remove the environment variable AZURE_AUTHORITY_HOST and see if the issue persists.
Use a different authentication method, such as Azure Active Directory (AAD) B2C or Azure Active Directory (AAD) v2.
Check the Azure Functions runtime logs for any errors or warnings related to the AZURE_AUTHORITY_HOST environment variable.

A: If you cannot remove the environment variable AZURE_AUTHORITY_HOST, you can try the following workarounds:

Use a different environment variable, such as AZURE_TENANT_ID or AZURE_CLIENT_ID.
Use a configuration file, such as local.settings.json, to store your Azure Functions configuration.
Use a different authentication method, such as Azure Active Directory (AAD) B2C or Azure Active Directory (AAD) v2.

A: To prevent the issue from occurring in the future, you can take the following steps:

Remove the environment variable AZURE_AUTHORITY_HOST from your system.
Use a different authentication method, such as Azure Active Directory (AAD) B2C or Azure Active Directory (AAD) v2.
Use a configuration file, such as local.settings.json, to store your Azure Functions configuration.

A: Some best practices for using environment variables in Azure Functions include:

Only use environment variables that are required for your Azure Functions application.
Avoid using environment variables that are not required for your Azure Functions application.
Use a configuration file, such as local.settings.json, to store your Azure Functions configuration.
Use a different authentication method, such as Azure Active Directory (AAD) B2C or Azure Active Directory (AAD) v2.

In conclusion, the environment variable AZURE_AUTHORITY_HOST can cause an error when using the func command line tool, specifically the error message "Exception has been thrown by the target of an invocation." By following the troubleshooting steps and workarounds outlined in this article, you can resolve the issue and prevent it from occurring in the future.