[exim] hold_domains works almost always

Hello.
When I uses both options in exim:
hold_domains=<sample domain here>
queue_smtp_domains=*

and i send, for example, 5-10 mails to domain mention in "hold_domains",
exim sends a few mails to destinations server. But not all of them. 2-4
mails are sended, rest of them is keeped locally, and main log mark this
mail as "domain is held" (and this is correct).
Is it something that i missed reading documentation?
Regards,
Marcin