After several weeks of waiting the technical issues got solved. The upload to @threespeak is working again. The team experienced serious server and database issues as pointed out here.
Yesterday I saw a note on the Telegram chat and tested it. Tried to upload one of my videos. Yes, it works again! Good news the Team fixed the problems and the service is back to full usablility.
I still have several cool videos for you guys in the pipeline that I took in the meantime. Will post them in tho coming days, step by step. Stay tuned!