[Koha] put on hold a book

[regina kivuyo]

i want to put on hold a book but i receive the message Cannot place hold

   - *Too many holds: *Witness Kalomo
   <http://www.opac.mlrc.saut.ac.tz:8080/cgi-bin/koha/members/moremember.pl?borrowernumber=51>has
   too many holds.

 but it allow me to hold a book ,how to remove the book
-- 
regina