Are you using your phone for this? cause it works when you work on a pc or a laptop.
I think you know the link pasting procedure so just follow that when on desktop.
Hope this helps.
Happy blogging:)
First you post your video to youtube then copy the youtube link and then on tripoto site go to publish trip you will see the option upload video paste your link there and hit publish it will upload one more thing don't use your mobile device use your desktop browser