Yes, it is a "them issue" today.
As for data uploads there are two possibilities. Your data may just be uploading just fine but the problem is with the front end of the dashboard and you currently can't see your data until they fix it. Hopefully then when the dashboard comes back all your data will be there an nothing will be missing.
But what could also happen is that the dashboard site comes back and there is also missing data. In this case there is nothing you can do to back-fill missing data. The Ambient weather stations are not loggers, meaning that they don't store any data to later upload. Ambient stations are live update only, meaning they need constant connectivity to stream the data to some other place.
Because I upload with my Meteobridge to Ambientweather.net, I can see the performance of the Ambientweather.net upload and I do see the green check mark that the upload was successful. This clue tells me that likely the back-end looks good and your data is uploading successfully. This is good news, which leads me to believe that today's issue is just a front end website dashboard issue and the data is making it to their database. But you never know. We'll see what happens.