Steemit won't let me delete, hide or even modify my D.Tube video

Hi everyone,

I uploaded my first video

(.m4v-file, 1.3 GB) by using the D.Tube back end. It used to be playable for a few days, but D.Tube seemed to have trouble transcoding it to 480p because there is no hash shown in my back end. And now even the source file isn't playable:

Meanwhile I learned a couple of things about IPFS and Steemit and that I did everything wrong what I could do wrong with my first upload...

I transcoded my second video

into both source and 480p formats by myself, uploaded it directly to IPFS and referred the files to D.Tube. This worked perfectly, both formats are playing flawlessly and I was able to change the title and the snapshot hash.

But my first video won't let me do so. The only thing I see when trying to change ANYTHING is "Error transmitting to the blockchain":

I transcoded the video, uploaded it to IPFS and modified the hash in D.Tube. Error. I tried to only refer the 480p video. Error. I tried to change the title to "(Deleted)". Error. I tried to blank everything except the title. Error. I tried to modify the post in my Steemit blog, but there is no option to do so, there is no "edit" button, no "delete" button, nothing.

I don't want to delete the file or hide the post, I only want the video to be playable. But something seems to be wrong with the post itself since I could modify my second video without any trouble.

I appreciate any suggestion!