server start --insecure --address 0.0.0.0:51515 --server-username=XXX --server-password=XXX The instructions with htpasswd is outdated. Kopia doesn't use the htpasswd file anymore. I used the above "post arguments" (under advanced view) to get Kopia to work. Replace XXX with your chosen username and password. Repo username and password can be same or different. References: https://kopia.io/docs/installation/#docker-images https://www.youtube.com/watch?v=_WFjk4Ak0b0 https://github.com/kopia/kopia/issues/880