I’m not able to upload files to Koofr Vault and I’m getting an error: “Failed to fetch / net::ERR_H2_OR_QUIC_REQUIRED”. Why?

This error is usually caused by some extensions on antiviruses blocking the in browser encryption process. Some sort of proxy/antivirus that is sitting between your browser and the internet and causing this issue. Something is changing HTTP/2 into an HTTP/1 connection, which doesn’t work with Vault uploads. Whatever is the cause, is monitoring/changing your connection to our service and breaking it. Could be a VPN, proxy or antivirus. Try to disable it or whitelist koofr.net.

If you are using AdGuard, add koofr.net as Exclution in Filter HTTPS protocol. Open Settings, find Network and HTTP Filtering, choose Filter HTTPS protocol and then Exclutions. Add a new line and type koofr.net.