The issue will likely have to do with the SELinux contexts on the ID's .ssh directory (and maybe more). look to the contexts (in .ssh) to have a type of ssh_home_t.
This is similar to the SSH user file's required permissions (no rwx for group/other). I've not checked but it may be required on both ends (both source and target user's .ssh dir needs that same contexts).
This is an example of the "correct" contexts:
[account@hostname .ssh]# ls -alZ drwx------. account account unconfined_u:object_r:ssh_home_t:s0 . drwx------. account account unconfined_u:object_r:user_home_dir_t:s0 .. -rw-------. account account unconfined_u:object_r:ssh_home_t:s0 authorized_keys -rw-------. account account unconfined_u:object_r:ssh_home_t:s0 id_rsa -rw-------. account account unconfined_u:object_r:ssh_home_t:s0 id_rsa.pub -rw-r--r--. account account unconfined_u:object_r:ssh_home_t:s0 known_hosts [account@hostname .ssh]# ls -alZ drwx------. account account unconfined_u:object_r:ssh_home_t:s0 . drwx------. account account unconfined_u:object_r:user_home_dir_t:s0 .. -rw-------. account account unconfined_u:object_r:ssh_home_t:s0 authorized_keys -rw-------. account account unconfined_u:object_r:ssh_home_t:s0 id_rsa -rw-------. account account unconfined_u:object_r:ssh_home_t:s0 id_rsa.pub -rw-r--r--. account account unconfined_u:object_r:ssh_home_t:s0 known_hosts In order to fix the context, you can use sudo chcon -t ssh_home_t /home/username/.ssh/authorized_keys
sudo chcon -t ssh_home_t /home/username/.ssh/authorized_keys