As discussed before, I’ve made a backup (using yunohost backup) to migrate my server.
Upon restoration, I had a problem with nextcloud archive as described here : https://paste.yunohost.org/raw/isofatalav
The issue was that at some point, it wanted to use the kombayo.online domain which is deprecated (and has been for months).
I solved it by creating the domain just for the installation, then removing it again, but there’s a bug anyway (and I could not find an obvious instance of kombayo.onlinein the files)
Well it sounds like your nextcloud was installed on nextcloud.kombayo.online so you need this domain to be available on your destination machine to restore this app (granted it’s not 100% obvious)