Mpfr update breaks sysup

Hi all, I'm trying to do a sysup on my crux-3-3 (everything works perfectly, also plasma5...). The update begins and immediately hangs because, after connection to www.mpfr.org, the request sent for mpfr-3.1.6.tar.xz remains always awaiting response. Useless to try "prt-get sysup lock mpfr". What could I do to go on with update? Thanks