If you want to be able to send patches to authors directly from Darcs you may need to configure your system for sending email directly from the command line.
Note this is separate from your GUI email client’s configuration.
First, try testing
darcs send again using
--to email@example.com to send some patches to yourself. You should receive the message promptly. If not, some configuration is needed. Many people use the Postfix mail software and might find this helpful.
If you’re not comfortable with the idea of setting up your MTA (eg. Postfix), one fairly easy way to configure Darcs for sending email is to set up a program called Msmtp.
Have you successfully sent a patch to yourself?
If yes, there may still be problems causing some mail providers to silently ignore the message as spam. For example, in your email client view the message source and look for a bogus from domain, like
From: firstname.lastname@example.org, and if you’re using Postfix see this.
Another thing to consider is if the remote end has some kind of spam-prevention mechanism. For example, the darcs team bug tracker is backed by a moderation system: patches from new submitters must be approved manually (subsequent patches will go through automatically).
In the worst case, you could
darcs send -O to generate a patch bundle and email that by hand.