Polish characters in name field results 500 error

Hi,
i have fresh install of ralph and tried to populate it with polish names such as "Świat", "piętro" but im getting 500 sever error while POST. I don't think thats my env fault because your demo site also is giving 500 errs

/var/log/nginx/ralph-access.log:
POST /data_center/datacenter/add/ HTTP/2.0" 500 27 "https://*server_addr*/data_center/datacenter/add/" "Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:65.0) Gecko/20100101 Firefox/65.0

* Ralph version(from dpkg):
ii ralph-core 20190124.2 amd64 Ralph is an DCIM/CMDB - asset management for Data Centers/ Back Office.
* Operating system:
Ubuntu 18.04 LTS
* Method of installation: Deb