Azure function App exception error when receiving a post from a webhook

I have the below as an entry point to an azure function app, when I open postman and send a post to this function app I'm getting this error.

[Error] Executed 'Functions.http_trigger_from_vrli' (Failed,

The error is not remotely useful when I load this function app in local everything works, I'm able to do a post to https://localhost:7071/api/blahpost with the post data in the body. Code is executed on updateRT and all subsequent functions are completed successfully. It's just when I attempt to use azure functions app as the URL, I get a 500 and the above error. Am I doing something wrong with the route points that would cause this to 500 whenever it receives the payload? I can confirm via logger I'm getting past the if statement it is printing out the client IP address but doesn't appear to be executing the function inside the if statement. I'm debugging by cd'ing to the project in vscode then running "func start --verbose" again when I run it locally and send the post it works as expected.

here's an example of the payload

{ "alert_type": "RATE_BASED_WITH_GROUPS", "alert_name": "BlockMe", "search_period": "300000", "hit_oeprator": "GREATER_THAN", "messages": "[{"fields":[{"name":"msg","content":"primary credentials rejected - invalid user"},{"name":"count","content":"150"},{"name":"client_ip","content":"178.18.193.158"},{"name":"username","content":"stuff"},{"name":"status","content":"reject"}],"Count":150.0}]" }

also heres what im running at the root of my function app

app = func.FunctionApp(blah=func.AuthLevel.FUNCTION)
@app.route(route="blahpost")
def blahpost(req: func.HttpRequest) -> func.HttpResponse:
    logging.info('Python HTTP trigger function processed a request.')
    try:
        req_body = req.get_json()
    except ValueError:
        return func.HttpResponse(
             "Invalid JSON format",
             status_code=400
        )
    alert_name = req_body.get('alert_name')
    messages = req_body.get('messages')
    if alert_name == "BlockMe":
        logging.info(req_body)
        for item in messages['fields']:
            if item['name'] == 'client_ip':
                targetIP = item['content']
                logging.info(targetIP)
                response = irtUpdate.main(targetIP)
                logging.info(response)
                return func.HttpResponse(response, status_code=200)
    if alert_name == "USER-Lockout-Alert":
        logging.info(req_body)
        for item in messages['fields']:
            if item['name'] == 'username':
                username = item['content']
                logging.info(username)
    return func.HttpResponse("Function executed successfully.")