As you are getting an error while posting your images to Adobe stock you can check your settings and make sure that you have a correct setup by following this link How to publish photos from Photoshop Lightroom to Adobe Stock and social media
Please let us know if it helps.
I followed all the instructions you linked me to and it transferred 4 images (duplicates of what was already there), then I got the same message "Upload failed because of technical difficulties. Please try again later."
What do you think the issue is?
Nathan, Could you try signing out and then signing back into the creative cloud application using your Adobe ID?
Same result: Technical difficulties
I have the similar issue.
I deleted my published collection in Lightroom, added it back, added one image but when I try to publish I get the error: "Upload failed. For Adobe Stock plug-in to be active you must be signed in to Creative Cloud."
I'm having the same problem. Was working fine, then got finicky - sometimes would say "not signed in" and sometimes work. Now can't get it to work at all. I've tried restarting lightroom, signing out and back in, but doesn't help.