List of best mirrors for IP address 3.15.229.15, located in an unknown country.
I am very sorry, but no mirror was found. Feel free to download directly:
http://mirrordirector-mb.raspbian.org/raspbian/pool/main/d/dovecot/dovecot-mysql_2.3.21.1+dfsg1-1+rpi1+b1_armhf.deb