Some projects won't respond to rest API ../rest/stats/proj/%s/iter/%s?word=true

Hi there,

Some project will never answer rest request to have the statistics of one iteration
The URL is as following, where the 1st %s is the project name and the 2nd, the project iteration :
https://fedora.zanata.org/rest/stats/proj/%s/iter/%s?word=true

This match with documentation : https://zanata.ci.cloudbees.com/job/zanata-api-site/site/zanata-common-api/rest-api-docs/ns0_translationStatistics.html

You can reproduce this bug using the following code :
https://github.com/Jibec/fedora-zanata-statistics

Thanks for your help !