Why my foreman cannot show the puppet agent reports?

Support
1

the error message is /var/log/syslog
Report processor failed: Could not send report to Foreman at
https://puppetserver.***.com/api/reports: invalid byte sequence in UTF-8

os: ubuntu 12.04.1
foreman 1.9.3
puppet 3.8.3
ruby 1.8.7

how can i do?