RESOLUTION 1:
Check the permissions on the authorized_keys files:
ls -al /var/opt/quest/home/questusr/.ssh/authorized_keys
------------------------
-rw-r--r--. 1 questusr questgrp 203 Aug 22 12:00 authorized_keys
------------------------
ls -al /var/opt/quest/qpm4u/pmpolicy/.ssh/authorized_keys
------------------------
-rw-------. 1 pmpolicy pmpolicy 1740 Jun 1 17:27 authorized_keys
------------------------
RESOLUTION 2:
The SeLinux context of the authorized_keys files may have changed.
Check the following files:
/var/opt/quest/home/questusr/.ssh/authorized_keys
/var/opt/quest/qpm4u/pmpolicy/.ssh/authorized_keys
E.g
ls -alZ /var/opt/quest/home/questusr/.ssh/authorized_keys
------------------------
-rw-------. pmpolicy pmpolicy system_u:object_r:var_t:s0 authorized_keys
------------------------
If you made any changes to the Selinux context for these files, then ensure that they are still correctly configured.