Uploading New Photos to Lightroom Web Fails Consistently

I am currently using the latest version of the Lightroom webapp and attempting to upload new photos, however every attempt fails. I have plenty of remaining cloud storage space, and yet I cannot upload any new photos. I am not doing anything crazy, just trying to upload .NEFs from a Nikon Zf (which has always worked fine in the past) but every time the first 4 or so “load” completely (the upload bar for the images reaches the end) then they fail to turn green and complete the upload; remaining photos in the upload queue never get a chance to upload either because the first 4 never complete and the system only seems to want to process 4 at a time.