I'm running into a really weird issue and I would appreciate any guidance on what I'm doing wrong. So I recently applied for an API key here on Stack Exchange and it went through fine. So let's say (for example) I received the following API key:

abc3efghijk1mnop2rstuv

So using this key, I'm attempting to run a simple query like:

https://api.stackexchange.com/2.0/info?key=abc3efghijk1mnop2rstuv&site=stackoverflow

And I get the message:

{
    "error_id": 400,
    "error_name": "bad_parameter",
    "error_message": "`key` doesn't match a known application"
}

Am I using the API key correctly?

Note that I didn't want to post the real API key here for obvious reasons but if need be I can provide it.