Unable to create new project on a self hosted KoBoToolbox server


I;m facing the following issue with new installation of KoBo:

System is Ubuntu 20.

I have a line in error log:
2020/09/18 08:33:09 [error] 41#41: *1 connect() failed (111: Connection refused) while connecting to upstream, client:, server: kobo
.ulaanbaatar.mn, request: “GET /service_health/ HTTP/1.0”, upstream: “uwsgi://”, host: “kobo.ulaanbaatar.mn”

Please help.