I don't personally have an API key, I just use the API key of the weather stations around me. I did create a wunderground login the other day, so I'll go poke around the website now. I've been using Blue Iris Software and Blue Iris Tools for a long time, I registered here 8 years ago. I've never had any gremlins or anything until just the other day. Still have no clue why it started working again.
Oh, my Ambient Weather WS-2902 has been reporting to it rock-steady for the last year but from '21 to about fall of '23 it was on again off again, sometimes offline for 1 or 2 days then back on for 5 or 6.
And prior that that my Davis Instruments Vantage Vue worked with WU great from 2012 to about 2015 which is when IBM acquired WU, then it was up/down again for a time.
I'm just saying that WU has a history of periodic issues and it's not my equipment or just me. There are many IPCT posts from users that have had issues with WU over the years. So I generallly suggest to people to hold on, it'll come back.....for a time.
If you read the writeup in Wikipedia about them you'll see a stormy (sorry) history of being handed off and sold numerous times which likely contributes to their reliability and consistency of operation.