Improve album artwork scrapers

Hello,

I use the Universal Scapers which generally yield good results. But when I comes to cover fetching, the album scraper does not find a cover for about the half or more of my albums. The albums are named accuratly.

Are there tricks to improve the results?

I’ve read somewhere, that sometimes the serves are overloaded and that’s why they return no result. Is there a way to scan again to notfound covers?

Best Thanks!