[SOLVED] no cover art in album view

[TheOldPresbyope]

Hello,

I'm having my database attached via the media sever functionality of a Fritz!Box router.
In tag view, player view and full mode player, the album covers are displayed - no issue.
But in album view all covers are represented by a broken image. Also the cover art preview
(right column) on the tag view screen.

I tried everything I found here (clear, regenerate cache) but nothing helped.  

Any ideas?

Before jumping on my horse and ridding off in all directions, I'd like to be sure about your basic files. Zip up one entire album directory, upload it to a file-sharing site of your choice (DropBox, Google Drive, whatever) and send me the link by private message.

Regards,
Kent