First of all, bear in mind that it’s not the cover on your computer that is recovered. There is a process that retrieves an album cover based on the title and the artist of the music being played.
The process of retrieving the covers is not synchronized with live broadcasting. So if this is the first time your music is being played live, there may not be a cover. This can also happen if you’re broadcasting music that is not well known.
We therefore invite you to put a default cover in your Radio Manager under Settings > Covers and Titration. This way, when the live feed doesn't find a cover, it will be able to use the one you set by default.