The cause of the problem appears to be that ofbiz now defaults to using
HTTPS, but URLs, created to access content uploaded to ofbiz will use HTTP.
Ofbiz responds to these content requests with a 301 Redirect which is not
handled by Apache FOP when resolving URLs.
One solution might be to ensure Apache FOP is configured with certificate
authority information, meaning it can access resources using the HTTPS
scheme, but this might be difficult to handle in cases involving localhost
or behind reverse-proxyies.
I suggest using the data-uri scheme (https://tools.ietf.org/html/rfc2397)
to embed the data describing content, such as logo images, directly in the
XML processed by Apache FOP.