[Beemer2]

I'm confused about whether it is a bad thing to select more than one source to download metadata. At present I have three selected and am wondering if this is the reason I have the following problem:

If I select a single book with missing metadata and use download metadata there is no problem. However if I select more than one book and use bulk download of metadata it always fails to download the metadata.

Or is there some other reason for the failure?