perl-Net-SSH2-0.56-1.fc23.x86_64 contains a bug that breaks authentication using public keys, see https://github.com/rkitover/net-ssh2/issues/28. This bug got fixed upstream in version 0.57_03. It would be very nice to get the fix included in Fedora as well.
This is a developer, alpha release. I won't update to it; however, I'll include your fix in Fedora -- it seems reasonable and simple enough.
perl-Net-SSH2-0.56-2.fc23 has been submitted as an update to Fedora 23. https://bodhi.fedoraproject.org/updates/FEDORA-2015-7f1baa0c2f
perl-Net-SSH2-0.56-2.fc23 has been pushed to the Fedora 23 testing repository. If problems still persist, please make note of it in this bug report. If you want to test the update, you can install it with $ su -c 'dnf --enablerepo=updates-testing update perl-Net-SSH2' You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2015-7f1baa0c2f
perl-Net-SSH2-0.56-2.fc23 has been pushed to the Fedora 23 stable repository. If problems still persist, please make note of it in this bug report.
This package has changed ownership in the Fedora Package Database. Reassigning to the new owner of this component.