Vidyard provides the ability to allow your players to autoplay if desired. The ability to change this can be found within the General Player Settings of a particular player, or the Default General Player Settings if you wish to allow any newly created players to have a particular setting as the default.
You can also set autoplay on each embed using query strings.
You have noticed that a player on your page is auto-playing, but the General Player Settings suggest that autoplay is set to OFF.
It's very likely that you have a query string on the embed code which overrides any of the default player settings.
It will look something like the below:
A query string of autoplay=1 indicates that the player will autoplay. autoplay=0 switches autoplay off.
You can in theory have multiple players that contain the same video. Therefore another possibility is that you have a player with the same video on your website, but you have been looking at the settings for another player.
To ensure that you are looking at the correct player, check for the player UUID embed code via the browser's Page Source (generally accessible through a right click). The UUID will show after 'vidyard_embed_code_' (in bold above). Once you have copied that, you can search using the UUID from the dashboard and check if the settings are the same as what you were looking at previously.
You can adjust the autoplay=1 value to autoplay=0 to override the player settings or remove it from the embed so that the Vidyard General Player Settings are used.
If you were looking at an incorrect player and have no query strings, simply update the relevant player settings so that Autoplay= OFF.