Thank you. I solved it by desactivating the last lines of "modsecurity.conf"
The lines I desactivated was:
- SecRule MULTIPART_UNMATCHED_BOUNDARY "!@eq 0" \
- "id:'200004',phase:2,t:none,log,deny,msg:'Multipart parser detected a possible unmatched boundary.'"
After importing the language, I activated these lines for security.