Error code 0x20200259

Glad it's working for you now. Not sure what issue you were seeing intially.  If you run into problems again let us know. If you send us a screenshot it might help us see what's going on.

We have the supported video formats documented here (or there is a link in product at the bottom of the upload page): https://stream.microsoft.com/en-us/documentation/stream-formats/

And upload error codes documented here: https://stream.microsoft.com/en-us/documentation/stream-portal-understanding-playback-errors/