Again: if you have a dedicated VirtualHost (which you do

) then:
- use ProxyPass (which you are, so good
)
but do NOT use:
...
--url-prefix means calibre-server expects all internal urls to appear in
http://www.dom134.com/calibre, which is useful in the event that the same server is serving something else in another directory.
Using it means you need to use a RewriteRule to redirect only those subdirectory urls to calibre-server on port 8080.
Since you are using a VirtualHost, you don't need that and can use ProxyPass instead, to forward
everything as-is.
You can use an --url-prefix, but it is silly and unnecessary.
An apache ServerName expects to see the servername, not an url. An url is a ServerName followed by an optional directory/filename...
tl;dr Why does your ServerName have a "/calibre" at the end?