Hello,
during (re)installation of yunohost, where I entered my host-name, it said “DynDNS subdomain not available”.
(After entering it anyhow, and proceeded the installation, it came back to that window).
Is the nohost.me DNS down, or did I do something wrong?
When you reinstall your YunoHost instance from scratch, except if you restore it from a backup, you should ask for delete/reinitialize your domain before in order to reuse with it during your new installation.