I see that you are adding YouTube videos but by selecting the "Source Type" as "Self Hosted / External URL" in your video form.
Instead, kindly select the "Source Type" as "YouTube URL" and add your video URL in the "YouTube URL" field.
Regarding the License Key:
We use the Joomla's native
URI::root() function to detect the site URL. But, we a strange issue on your website. We see that your website address includes capital letters and that fails with the license key validation.
Solution:
1. Kindly open the file below,
{SITE_ROOT}/components/com_allvideoshare/tmpl/player/html5.php
2. Find the line (#113) below,
'siteURL' => URI::root(),
3. Replace it as follows,
'siteURL' => strtolower( URI::root() ),
4. Save the changes and check now.
Hope this solved your issue!
I promise that our next version would include this fix. So, no worries about the future updates.