The folder must be shared with the selected user.
ownCloud does not share the folder and gives the error "no users or groups found matching Firstname Lastname@otherserver.com (or similar, my ownCloud is not in English).
Operating system: raspbian on raspberry pi 3
Web server: apache
ownCloud version: 9.0.4
This issue has been discussed here: https://central.owncloud.org/t/federated-sharing-with-spaces-in-usernames/1878. If you need any more details, please let me know.
I did test a few more versions.
OC 8.2.7 is working.
OC 9.0.4, OC 9.0.5RC1, OC9.1.1RC1 are NOT working. So it fails for all OC9.0+.
If I use the core/js/sharedialogview.js from OC 8.2.7, it works in OC 9.1.1RC1!
@tflidd thanks for the info. Looks like sharedialogview.js from 8.2.7 uses the old API endpoint.
So this means the new API endpoint might have trouble with spaces.
Fix is here #25967