Installation fails: Couldn't connect to server

I’m trying to install OnlyOffice Docs on my VPS following the instructions, but am getting stuck at the step “Add GPG key”:

root@snowflake-1:~# curl -fsSL | gpg --no-default-keyring --keyring gnupg-ring:/tmp/onlyoffice.gpg --import
curl: (7) Couldn't connect to server
gpg: no valid OpenPGP data found.
gpg: Total number processed: 0

Hello @kevang

We are aware of this issue.
Currently, it may take several attempts to reach Ubuntu key server to get response.
Please try obtaining the key few more times until it reaches key server.

The GPG public key is also available from via this page.